This sample would be classified in the 'fun' category of neat things you can do with MCML and animations. Enjoy...!

<Mcml xmlns="http://schemas.microsoft.com/2006/mcml"
   xmlns:sys="assembly://mscorlib/System"
   xmlns:me="Me">

 <UI Name="Move">

  <Locals>
   <!-- A ListDataSet that handles content / order change events -->
   <ArrayListDataSet Name="MyList">
    <Source>
     <sys:String String="a"/>
     <sys:String String="b"/>
     <sys:String String="c"/>
     <sys:String String="d"/>
     <sys:String String="e"/>
     <sys:String String="f"/>
     <sys:String String="g"/>
     <sys:String String="h"/>
     <sys:String String="i"/>
     <sys:String String="j"/>
     <sys:String String="k"/>
     <sys:String String="l"/>
     <sys:String String="m"/>
     <sys:String String="n"/>
     <sys:String String="o"/>
     <sys:String String="p"/>
     <sys:String String="q"/>
     <sys:String String="r"/>
     <sys:String String="s"/>
     <sys:String String="t"/>
     <sys:String String="u"/>
     <sys:String String="v"/>
     <sys:String String="w"/>
     <sys:String String="x"/>
     <sys:String String="y"/>
     <sys:String String="z"/>
    </Source>
   </ArrayListDataSet>

   <!-- A timer that fires every now and then to kick off a move event. -->
   <Timer Name="Timer" Interval="100" AutoRepeat="true" Enabled="true"/>

   <!-- Values that hold the old and new index to used with the Move() method -->
   <!-- to affect the position of individual items in the ArrayListDataSet. -->
   <sys:Int32 Name="OldIndex" Int32="0"/>
   <sys:Int32 Name="NewIndex" Int32="0"/>

   <!-- A random used to generate values for OldIndex and NewIndex. -->
   <sys:Random Name="RandomGenerator"/>
  </Locals>

  <Rules>
   <!-- A rule that evaluates for each tick of the timer. -->
   <Changed Source="[Timer.Tick]">
    <Actions>
     <!-- Generate a random start and end index -->
     <Invoke Target="[RandomGenerator.Next]" maxValue="[MyList.Count]" ResultTarget="[OldIndex]" ExclusiveApply="false"/>
     <Invoke Target="[RandomGenerator.Next]" maxValue="[MyList.Count]" ResultTarget="[NewIndex]" ExclusiveApply="false"/>

     <!-- Invoke the Move() method which will modify the order -->
     <!-- of the ArrayListDataSet -->
     <Invoke Target="[MyList.Move]" oldIndex="[OldIndex]" newIndex="[NewIndex]"/>

     <!-- View the changes made to the indexes using a tool like DebugView to view. -->
     <!-- See http://www.microsoft.com/technet/sysinternals/utilities/debugview.mspx -->
     <DebugTrace Message="Moving from from {0} to {1}">
      <Params>
       <ObjectPath ObjectPath="[OldIndex]"/>
       <ObjectPath ObjectPath="[NewIndex]"/>
      </Params>
     </DebugTrace>
    </Actions>
   </Changed>
  </Rules>

  <Content>
   <Repeater Source="[MyList]" Layout="HorizontalFlow">
    <Content>
     <!-- The UI used for our item, passing in the Index and value from -->
     <!-- the ArrayListDataSet. -->
     <me:Item Index="[RepeatedItemIndex]" Value="[RepeatedItem!sys:String]">
      <Animations>
       <!-- Each time the index changes for the ArrayListDataItem -->
       <!-- run this animation. Depending on the timer interval this can have -->
       <!-- a cumulative effect as the animation is applied across the range -->
       <!-- determined by the random number generator for OldIndex and NewIndex. -->
       <!-- A timer interval of 100 or less demonstrates this effect well. -->
       <Animation Type="Move">
        <Keyframes>
         <PositionKeyframe Time="0.00" RelativeTo="Current" Interpolation="SCurve"/>
         <PositionKeyframe Time="0.15" RelativeTo="Current" Value="0,-20,0"/>
         <PositionKeyframe Time="0.35" RelativeTo="Final" Value="0,-20,0"/>
         <PositionKeyframe Time="0.50" RelativeTo="Final" Interpolation="SCurve"/>
        </Keyframes>
       </Animation>
      </Animations>
     </me:Item>
    </Content>
   </Repeater>
  </Content>
 </UI>

 <UI Name="Item">

  <Properties>
   <!-- These are set as each item is created in the repeater. -->
   <Index Name="Index" Index="$Required"/>
   <sys:String Name="Value" String="$Required"/>
  </Properties>

  <Rules>
   <!-- Bind the index. Note when the index changes we see the change reflected -->
   <!-- in the visuals without any explicit code setting the value. -->
   <Binding Source="[Index.Value.ToString]" Target="[IndexLabel.Content]"/>
  </Rules>

  <Content>
   <Panel Layout="VerticalFlow">
    <Children>
     <!-- The text from the ArrayListDataSet which is repeated. -->
     <Text Content="[Value]" Color="White" Font="Courier New, 24"/>
     <!-- The index of the item in the ArrayListDataSet. -->
     <Text Name="IndexLabel" Color="Gray" Font="Courier New, 12">
      <Animations>
       <!-- Each time the index changes animate the number beneath the text. -->
       <!-- Like the other animation this can have a cumulative effect -->
       <!-- as the timer interval is lowered. -->
       <Animation Type="ContentChangeHide">
        <Keyframes>
         <PositionKeyframe Time="0.00" RelativeTo="Current" Interpolation="Log"/>
         <PositionKeyframe Time="0.50" RelativeTo="Current" Value="0,100,0"/>
         <AlphaKeyframe Time="0.00" RelativeTo="Current" Interpolation="Log"/>
         <AlphaKeyframe Time="0.50" RelativeTo="Current" Value="0"/>
        </Keyframes>
       </Animation>
      </Animations>
     </Text>
    </Children>
   </Panel>
  </Content>

 </UI>

</Mcml>