I like putting vocals through a guitar amp with a built-in reverb like a Deluxe or a AC-15. Makes it sound like an old record. The guitar player in our band showed me this trick recently where you can hold an IPhone up to a guitar pickup and play some audio through the speaker (of the IPhone) and the guitar pickup will respond to it and play the audio back through the amplifier. It's pretty amazing.

Someone should make a bitcrusher pedal that crushes the signal the same way a 16-bit MPC-2000 would. It would be the world's first real Hip Hop pedal!