When I first inherited my new MacBook--and I am forever grateful, might I add--it came with some very nasty fan noise. It turns out that some Geek Squad reject took something blunt and heavy to the top of the keyboard and smashed the underlying metal into the fan. Luckily, a quick stop by the Apple shop on campus and a few days away on a camping trip cured all of my fan woes--and at no cost to me, at that.
Now, it's quiet as can be: no more propping one corner up with a guitar pick or shuffling papers on my desk, a la Jenga. It truly is a beautiful thing.
Ssshh... Can you hear that?
...I didn't think so.