I have some Folding@Home screenshots
here (you will probably find the graphical client most interesting, though I have screenshots of the console version as well).
Prime95... uh... well... searches for Mersenne primes...
I can get you a screenshot of the client when it's in "torture test" mode, the mode that I - as well as many others - use it in to test the stability of our systems. In that mode it tries to calculate already known mersenne primes, and compares its results with the known ones. If the results are off, the system must not be producing the proper answers, and it is then best to back off a bit on the overclocking a bit and try again, to make sure the system is stable.