If you’ve installed the February CTP for WPF/e (which allows for WPF in the browser on PCs and Macs), then you’ll want to check out this cool Scratchpad app on your Tablet PC.
I’ll see if I can post some WPF/e and Javascript code that shows how to create hand-drawn “ink” like this. For those of us, that are used to the smooth, pressure-sensitive ink, the pencil-drawn paths in Scratchpad don’t measure up, but it is cool to see what can be done. For now, the simple line-segment paths are like those that you’ve probably seen in various Flash-based apps. It’s a start.