Reverb effectsReverb, or reverberation, effects are echo effects that make you sound like your playing in a large room. Traditionally they were spring based, usually inside the amplifier there was a box with springs going from one side to the other. A driver vibrated the spring in one end and a microphone/pickup "listened" on the other side of the spring. The spring continued to vibrate after the driver stopped "shaking" the spring and thus an echo was produced.
LinksEquinox - PT2399 based reverb.
Sewer Pipes Ring-Verb - Simple PT2399 based reverb.