Silverlight XAML Primer 13: Starting and Stopping Animations: Listing 1: Defining Storyboards within event triggers.
<Canvas xmlns="http://schemas.microsoft.com/client/2007">
<Canvas.Triggers>
<EventTrigger RoutedEvent="Canvas.Loaded">
<BeginStoryboard>
<Storyboard>
<DoubleAnimation AutoReverse="True"
From="80" To="200" Duration="0:0:3"
Storyboard.TargetName="tbHello"
Storyboard.TargetProperty="(Canvas.Left)"
RepeatBehavior="Forever"/>
</Storyboard>
</BeginStoryboard>
</EventTrigger>
</Canvas.Triggers>
<TextBlock Name="tbHello"
Canvas.Left="36" Canvas.Top="80"
Foreground="Maroon" FontFamily="Verdana"
FontSize="24" FontWeight="Bold"
Text="Hello From Silverlight!">
</TextBlock>
</Canvas>