A chumsquare is a friend of yours who's pretty average. You know what kind of a day you're likely to spend with a chumsquare - nothing out of the blue or entertaining is likely to happen.
Families of chumsquares are common (we're pretty sure the chumsquare gene is passed on) and they generally watch alot of television in silence.
RB: So is Finn going clubbing with us tonight or not?
TM: Nah, he's set on staying home and being a chumsquare.
n. software that is no longer sold or supported by the original publisher / developer, often found as free downloads on the internet because it cannot be obtained elsewhere. Not legal, but often seen as morally acceptable because the company that made it is no longer selling the title, nor releasing it as freeware, therefore abandonware is "keeping the gamealive", so to speak.
Doom II is not abandonware because idstill sells it, while The Incredible Machine is not sold, therefore is abandonware.