My TiBook has been crashing for no apparent reason. I did everything to eliminate causes: removed RAM, ran hardware tests, ran CPU-intensive software overnight, tried different OSes, reinstalled OSes, ran surface scans of partitions, ran file and filesystem checks, etc. The only thing I noticed for sure is that I was always doing something on the keyboard when it froze, and usually happened in my lap (only one freeze yesterday while at my desk, but several of them on my lap).
So after four Apple tech support guys, I thought some more and decided to run some more tests. I hit the space bar repeatedly. Freeze after a few seconds. Try again, in Mac OS X. Freeze. Try again, no freeze. Why no freeze? Doh, it is on the desk this time. Put it on my lap. Freeze.
Apple is sending me a new keyboard; hopefully this does the trick. If not, at least I can send it in to them with a repeatable test case.
And Yes, I sorta do wish I had an iBook 14" right now, instead of this thing. Too fragile, horrible AirPort range. Sigh.