And I don't mean a Montreal Canadiens fan. (o;
My Mini's fan had been blowing loudly after I upgraded to Snow Leopard. I found the solution here:
http://support.apple.com/kb/HT3964?viewlocale=en_US
Resetting the SMC for Mac Pro, Intel-based iMac, Intel-based Mac mini, or Intel-based Xserve
1. Shut down the computer.
2. Unplug the computer's power cord.
3. Press and hold the power button for 5 seconds.
4. Release the power button.
5. Attach the computers power cable.
6. Press the power button to turn on the computer.
Reminds one of the Zap-The-PRAM ritual.