A sampling of VML:
Vector Markup Language from Microsoft runs only in IE 5or above, but supports the creation of imagery in the browser.
Drawing and animating a line a sort of simplest case
Letting the user draw a line dragging the mouse from one point to another to draw and move lines.
Building a wall of color -- something a bit simpler
Drawing a translucent rectangle over an image and dragging it around
Playing with bezier curves
A sampling of effects (opacity, fill, strokewidth etc.)
A few more effects (including rotation of a group)
Rotating an oval with a picture in it.
Here's a URL that describes the rest.