Chorus effects

A chorus effect makes the guitar sound like multiple guitars playing.

Links

Boss CE-2
Little Angel - A simple chorus effect based on the PT2399 IC.
Noise Ensamble - An even simpler chorus based on the PT2399 IC.
One Chip Chorus - Another PT2399 based chorus, this one even simpler than the Little Angel.
Small Clone Chorus

PT2399

The PT2399 is used in a lot of chorus effects but it does suffer from a few problems, lockup being the most annoying. Here's some information on how to solve that:
PT2399 Anti lockup