There are a lot of things you can do with your paycheck-stub, and a lot of things you should be looking out for. Are you paying too much in taxes? Is your employer making the proper deductions? Sure there's fun stuff -- like getting a loan or playing paycheck-stub lotto, but there's also serious stuff too.
I think your paycheck-stub is one of the most important legal documents you see every week. It's a shame most of us don't take the time to figure out what's on there.