I'm running Mac 10.5.8 (Leopard) and my exposé has been weirding out on me. It randomly starts shuffling my windows around, and it won't go to sleep (my family generally sleeps the computers while in town). It is connected on a network to an older mac (10.4 I believe), runs on airport. My spaces is turned off. Other than the weird random exposéing and not going to sleep (which I suspect is because it is triggering the exposé buttons while asleep) there seems to be nothing wrong with it.
I have not played any fullscreen games since (and for long before) it started, though I have been playing some Quake Live, but intermittently and not immediately before this started. Another thing to note is that after playing a fullscreen game (particularly SWBF or CIV 4), the top bar of the screen (where the File, Edit, Time and Airport stuff are) is always scrunched up when I exit the game.
A side note; it weirds out even more when I open system preferences making it next to impossible to use. It's almost as if someone is controlling the computer from afar and is trying to keep me from getting to something.
Regarding the icons and top bar being scrunched up, that's normal. Just relaunch Finder and things will go back to normal. Although if you take screenshots while in SWBF, the icons get screwed up and you'll have to fix them yourself.
It's a bug that Apple hasn't fixed since 10.5.0.
hmm, do you see problems in any non-apple program? Basically anything that uses the standard apple APIs for the window (almost any regular mac program would use them).
I've found that as time goes on, a computer gets more and more buggy (yes, this does happen to macs too. It's just not noticed as much since you get an upgrade every year :P ), and every once in a while it just needs a fresh start. Backing up everything and doing a full reinstall usually fixes most problems, although this isn't needed if you plan on upgrading to snow leopard soon.