A while back I came across a fun bit of code on CodeProject that used alpha blending to animate a fish swimming around on the screen. I've been toying around with that code on and off for awhile and it finally has turned into a whole bunch of fish swimming around on the screen.
If you've been dieing to have fish swimming around on your screen the wait is over. Check it out over at CodeProject.
(This is written against the .NET 4 RC. You may need to download this for it to work.)