I have an Xbox 360 with what I think is an overheating problem. In some games, after a while of playing, the colors just go crazy, and I have to turn it off and wait a while for it to work, while in others there's no problem. It has had a repair attempt which didn't change anything, and I don't really want it anymore. I want to sell it, but I have no clue what I might be able to sell it for, seeing as it's broken for some but not all games and otherwise functions well. 
 
Any input would be awesome.

Honestly, your 360 is living on borrowed time and will soon RED RING. So very sorry to hear about your future loss. I know how you will soon feel. :(

Sell it on eBay as broken and maybe someone will buy it and repair it. Better then nothing. If all else fails throw it off a bridge for the fun of throwing stuff off a bridge.