I can't find a picture online, and the ones I took are [possibly] lost in some backup, but 10-15 years ago at the Corvallis, OR, Da Vinci Days
Kinetic Sculpture race someone fielded a pedal-power vehicle made from a yellow plastic septic tank on UTV mudder tires. It had a crew of 4-6 plus coxswain and a sound system playing a rap version of Yellow Submarine.
Found it!
http://www.oobject.com/category/lots...ow-submarines/