Live Pivot from Microsoft Labs provides a great tool to show data, thus i have created a supporting ActionResult for MVC to easy the creation of the data.
This code show an example of data from a fake compaints system that uses the cusstomer ActionResult and linq to generate the data

The url that returns the CXML must have the cxml extension!!!!!! thus modify the RegisterRoutes / RegisterArea to ass a MapPath for a url ending in CXML to a controller and action (see code at end of page) <– that took a while to find out why Live Pivot would not read it!!!!

public ActionResult Index(DateTime startdate, DateTime? endDate)
{
    ComplaintDataContext model = new ComplaintContext();

    var items = model.Complaints.Where(m => m.ComplaintDate > startdate);
    if (endDate.HasValue)
    {
        items = items.Where(m => m.ComplaintDate < endDate.Value);
    }

    var action = new XmlLivePivotAction<Complaint>("Customer Complaints");
    action.FacetCategories.Add(new FacetCategory<Complaint> { Name = "Location", Type = FacetType.String, Action = m => m.Locaion});
    action.FacetCategories.Add(new FacetCategory<Complaint> { Name = "City", Type = FacetType.String, Action = m => m.City });
    action.FacetCategories.Add(new FacetCategory<Complaint> { Name = "Date", Type = FacetType.DateTime, Action = m => m.ComplaintDate.ToString("s") });
    action.FacetCategories.Add(new FacetCategory<Complaint> { Name = "Type", Type = FacetType.String, Action = m => m.Type });
    action.ItemName = m => m.ComplaintDescription;
    action.Id = m => m.ComplaintId.ToString();
    action.Items = items;
    action.Img = m => 0;
    action.ImageBase = Url.Content("~/content/dzc/dzc_output.xml");

    return action;
}

The above code is split into the following areas:
* Linq query to get the data
* Initializes a new instance of the XmlLivePivotAction class passing the Complaint as the generic type
* Set all the FacetCategories
* Set the other parameters
* return it!

The following is the source for the ActionResult and thier support classes:

    /// <summary>
    /// Xml action
    /// </summary>
    /// <typeparam name="Model">The type of item this will use within the collection</typeparam>
    public class XmlLivePivotAction<Model> : ActionResult
    {
        /// <summary>
        /// Initializes a new instance of the XmlLivePivotAction class
        /// </summary>
        /// <param name="name">Name of the collection</param>
        public XmlLivePivotAction(string name)
            : base()
        {
            this.Name = name;
            this.FacetCategories = new List<FacetCategory<Model>>();
        } 

        /// <summary>
        /// Gets or sets the enumerable collection of items
        /// </summary>
        public IEnumerable<Model> Items { get; set; }

        /// <summary>
        /// Gets or sets the name of the collection
        /// </summary>
        public string Name { get; set; }

        /// <summary>
        /// Gets the list of categories
        /// </summary>
        public List<FacetCategory<Model>> FacetCategories
        {
            get;
            private set;
        } // FacetCategories

        /// <summary>
        /// Gets or sets the location to the DZI
        /// </summary>
        public string ImageBase { get; set; }

        /// <summary>
        /// The schema for the pivot collection
        /// </summary>
        private readonly string P = "http://schemas.microsoft.com/livelabs/pivot/collection/2009";

        /// <summary>
        /// The override method to produce the xml output
        /// </summary>
        /// <param name="context">the context this is running in</param>
        public override void ExecuteResult(ControllerContext context)
        {
            context.HttpContext.Response.ContentType = "text/xml";
            context.HttpContext.Response.AddHeader("content-disposition", "inline; filename=output.cxml");
            using (XmlWriter writer = XmlWriter.Create(context.HttpContext.Response.Output))
            {
                writer.WriteStartElement("Collection", "http://schemas.microsoft.com/collection/metadata/2009");
                writer.WriteAttributeString("xmlns", "xsi", null, "http://www.w3.org/2001/XMLSchema-instance");
                writer.WriteAttributeString("xmlns", "xsd", null, "http://www.w3.org/2001/XMLSchema");
                writer.WriteAttributeString("Name", this.Name);
                writer.WriteAttributeString("SchemaVersion", "1");
                writer.WriteAttributeString("xmlns", "P", null, this.P);
                this.WriteFacetCategories(writer);
                this.WriteItems(writer);
                writer.WriteEndElement();
            }
        }

        /// <summary>
        /// Gets or sets the name function for the item(s)
        /// </summary>
        public Func<Model, string> ItemName { get; set; }

        /// <summary>
        /// Gets or sets the id function for the item(s)
        /// </summary>
        public Func<Model, string> Id { get; set; }

        /// <summary>
        /// Gets or sets the image index function for the item(s)
        /// </summary>
        public Func<Model, int> Img { get; set; }

        /// <summary>
        /// Write facet items
        /// </summary>
        /// <param name="writer">the xml writer</param>
        private void WriteItems(XmlWriter writer)
        {
            writer.WriteStartElement("Items");
            writer.WriteAttributeString("ImgBase", this.ImageBase);
            foreach (Model m in this.Items)
            {
                writer.WriteStartElement("Item");

                writer.WriteAttributeString("Img", string.Format("#{0}", this.Img(m)));
                writer.WriteAttributeString("Id", this.Id(m));
                string name = this.ItemName(m);

                if (string.IsNullOrEmpty(name))
                {
                    name = string.Format("Fault #{0}", this.Id(m));
                }

                writer.WriteAttributeString("Name", name);

                writer.WriteStartElement("Facets");
                foreach (var c in this.FacetCategories)
                {
                    string action = c.Action(m);
                    if (!string.IsNullOrEmpty(action))
                    {
                        writer.WriteStartElement("Facet");
                        writer.WriteAttributeString("Name", c.Name);
                        writer.WriteStartElement(c.Type.ToString());
                        writer.WriteAttributeString("Value", c.Action(m));
                        writer.WriteEndElement();
                        writer.WriteEndElement();
                    }
                }

                writer.WriteEndElement();
                writer.WriteEndElement();
            }

            writer.WriteEndElement();
        }

        /// <summary>
        /// Writes each of the categories
        /// </summary>
        /// <param name="writer">the xml writer</param>
        private void WriteFacetCategories(XmlWriter writer)
        {
            writer.WriteStartElement("FacetCategories");
            foreach (var c in this.FacetCategories)
            {
                writer.WriteStartElement("FacetCategory");
                writer.WriteAttributeString("Name", c.Name);
                writer.WriteAttributeString("Type", c.Type.ToString());
                if (c.IsFilterVisible.HasValue)
                {
                    writer.WriteAttributeString("IsFilterVisible", this.P, c.IsFilterVisible.Value.ToString());
                }
                
                if (c.IsMetaDataVisible.HasValue)
                {
                    writer.WriteAttributeString("IsMetaDataVisible", this.P, c.IsMetaDataVisible.Value.ToString());
                }

                if (c.IsWordWheelVisible.HasValue)
                {
                    writer.WriteAttributeString("IsWordWheelVisible", this.P, c.IsWordWheelVisible.Value.ToString());
                }

                writer.WriteEndElement();
            }

            writer.WriteEndElement();
        }
    } 
    /// <summary>
    /// Facet category
    /// </summary>
    /// <typeparam name="Model">The type of model this category will use</typeparam>
    public class FacetCategory<Model>
    {
        /// <summary>
        /// Initializes a new instance of the FacetCategory class 
        /// </summary>
        public FacetCategory()
        {
        } 

        /// <summary>
        /// Gets or sets the name of the category
        /// </summary>
        public string Name { get; set; }

        /// <summary>
        /// Gets or sets the type of the category
        /// </summary>
        public FacetType Type { get; set; }

        /// <summary>
        /// Gets or sets a value indicating whether to this is a filterable category
        /// </summary>
        /// <value>
        /// <c>true</c> if this instance is filterable; otherwise, <c>false</c>.
        /// </value>
        /// <remarks>Leave as null to ignore this</remarks>
        public bool? IsFilterVisible { get; set; }

        /// <summary>
        /// Gets or sets a value indicating whether to show the metatdata
        /// </summary>
        /// <value>
        /// <c>true</c> if this instance is meta data visible; otherwise, <c>false</c>.
        /// </value>
        /// <remarks>Leave as null to ignore this</remarks>
        public bool? IsMetaDataVisible { get; set; }

        /// <summary>
        /// Gets or sets a value indicating whether to show the word wheel 
        /// </summary>
        /// <value>
        /// <c>true</c> if this instance is word wheel; otherwise, <c>false</c>.
        /// </value>
        /// <remarks>Leave as null to ignore this</remarks>
        public bool? IsWordWheelVisible { get; set; }

        /// <summary>
        /// Gets or sets the name of the category
        /// </summary>
        public Func<Model, string> Action { get; set; }
    }
    /// <summary>
    /// Facet type
    /// </summary>
    public enum FacetType
    {
        /// <summary>
        /// the facet is a string
        /// </summary>
        String,
        /// <summary>
        /// the facet is a long string
        /// </summary>
        LongString,
        /// <summary>
        /// the facet is a number
        /// </summary>
        Number,
        /// <summary>
        /// the facet is a date time
        /// </summary>
        /// <remarks>
        /// use <c>value.ToString("s")</c> to export as ISO
        /// </remarks>
        DateTime,
        /// <summary>
        /// The fact is a link
        /// </summary>
        Link
    }

the Map route example

context.MapRoute(
                "CXML Path for compaints",
                "Admin/LivePivot.cxml",
                new { controller = "LivePivot", action = "Index", id = "" }
            );