Watch the Analog Delay Freakout online guitar lesson by Jeff McErlain from Guitar Effects Survival Guide
A neat little trick of a delay pedal is to utilize the pedal going into oscillation. What is happening is the pedal basically keeps repeating onto itself and in essence feedback. The effect is this very cool, and loud, UFO , sci-fi, sort of sound. It can be a lot of fun to experiment with and can be a very cool sound effect on a recording. I have heard Radio Head use this effect a few times on recordings. It's nice to be able to pull a few tricks like this out of your bag on a gig or in a session.