this happened to me daily during the summer before we put the AC in upstairs (where the xbox is) the other thing that would happen would be that the power source's light would be red and not provide power. when i had to do was turn the AC up full blast and unplug the powersource from the wall and the xbox. after about half an hour, the room was around 65F from about 90F, first I plugged in the power source, the light was yellow and then the xbox. everything worked fine from then on. If this happens, just dont use it for about an hour and it would be fine. Also, dont leave the xbox on if not playing. When it goes into standby, I believe some of the fans inside shutoff, causing a greater buildup of heat. If you must leave it on for an extended period, get a fan to blow air through it or chill the room with an AC.
hope this helps and wow, this is the longest post Ive ever written lol