I've spent some time playing with XUL which, from a Nerd's perspective, is pretty cool (and rhymes with XUL!). I created a Fantasy Football FireFox extension that is EXPERIMENTAL. It's a rough first attempt and I'll try to spend more time in the off-season enhancing it. Right now, it allows me to view the weekly projections and daily NFL news without having to sign in and the window stays on top of my screen. I like that because I can have FleaFlicker or Yahoo leagues open with the rankings window to the side.
If you're interested, try it. Just remember that it is experimental and by no means complete yet. It's the result of some dabbling for my own needs.