iPod touch CRASHING!? (sleep mode)

For some reason my iPod touch some times seems to crash when I turn it on after putting it to sleep by pressing the sleep/power button. Basically a bunch of randomly lines and junk scatter around on the screen. I also have a feeling this drains the battery, because my battery life has been rapidly decreasing. I am able to get the iPod touch to work again by holding the sleep/power + menu buttons. But that of course restarts it...and restarting takes a while, which is annoying. Has anyone else had this issue? Any ideas on why it happens or how to fix/prevent it? Sometimes I don't have the problem, but about 1/2 the time or more I have this problem.
Here's a video of the issue I encounter:

www.salsunproductions.com/misc/ipod_touch_crash2.mov
(5.4 MB, QT7 or later required)

PS: I encountered the problem even when I didn't have low battery, so I don't think that has anything to do with the problem.