Sometimes when I can't sleep, I go back into the computer room and gaze at a machine doing something menial and textual for a while. I used to do this with the family DOS computer before I even started school; there's something about slowly changing characters on a screen in a dark room that's almost… hypnotic.
Memtest[86+] works, SpinRite is also a good one. Back in my Windows days it used to be ScanDisk. In any event, I just watch this Matrix-style stuff go by in slowmo for a short while, and I'm ready to try sleeping again.
Stop looking at me like that.