Here’s a humongous barrel-type compost rig that can turn up to 500 lbs of a load using pedal-power. All the parts were made from bike drive trains and parts found around the shop. This might be overkill for a household, but might make sense for a small community garden. Definitely you’d get some exercise while you’re promoting aerobic decomposition.

Pedal Powered Compost Turner [Thanks, Phil Shapiro!]