Here is an interesting one. Typically with the Silverlight 1.0 object model you can access properties and methods directly through Javascript. Now given this you would expect that to dynamically set a Transform, for example a rotation on a TextBlock, you would do something along the lines of textblock.RenderTransform.TransformGroup.RotateTransform.Angle="45" or something to that effect. However this will error. To do this you actually have to create the Transform from XAML using the createFromXAML method.
So to add RotateTransform to a TextBlock you need to do the following:
var textblock = rootCanvas.findName('tb');
var trans = control.content.createFromXaml('<TransformGroup><RotateTransform Angle=\"45\"/></TransformGroup>');
textblock.renderTransform = trans;
and that will dynamically add the rotation to the TextBlock.