DONT DO THIS! I repair RROD's all the towel trick does it warp the motherboard within the 360 causing the gpu and cpu to reset and reconnect for a short amount of time. this will cause your 360 to be unrepairable.
Best thing to do is to send it back to M$ if its still under warranty.
However if you dont mind breaking the seals you can always fix it yourself.
Another 'quick fix' that has been floating around is to cover the xbox's vents with a towel. I don't know or think it will work but hey some ppl swear by it.
First unplug your xbox 360 but leave power cable in
Second wrap in 2 towels or more (Dry towels)
Third turn on and leave for 15-20 minutes
Four unwrap Turn off and let cool for 20 minutes
Five Plug in and play.
This will make xbox work without voiding warranty but only work for 1 day to 1 week at a time.