My favorite sick effect is actually a mic technique.
1. Sit guitarist in studio, plug his axe into
a Fender Champ, give him headphones.
2. Disconnect Champ's speaker, and connect to a long, long speaker cable, on the other end of which is an Auratone.
3. Take said Auratone out of the studio, down the hall, up the stairs, and put it in the clothes dryer.
4. Partially close the dryer door to taste.
5. Mic the dryer with a good LD condenser mic on the end of a long, long mic cable. Experiment with placement- the amount of room sound is key... (;-)
6. Feed the mic'd signal into said guitarist's cans.
7. Watch his expression! Then, print the result as he experiments with different settings on the amp....
Yes, I have done this, and yes, we did use it on a tune that got a fair amount of airplay...
Extra points if the dryer is running, I guess, although it might break the speaker wire and damage the finish on the Auratone a little- sort of a "Leslie from hell in a gravel crusher" effect.