Check out the kinetic sculpture race:
http://kineticsculpturerace.org/

There are a couple of others, but as far as I know this one was the first.

The first year I was in it, my pit crew and I (humans only) were
slogging through the mud flats by the Eel river, shin deep in mud,
carrying the machine by its axel. A news crew in a big 4WD Suburban had
gotten it stuck and wanted us to come push them out. We just looked at
each other and kept slogging. Thank heavens the Coast Guard had shut
down the Humboldt Bay crossing before I got there and tried it...

I did it twice. The second time we won the "nuts and bolts" award (for
looking the most like a hardware store, I guess).

Steve

steamer wrote:

--Taking a whack at building an "art car" in time for Burning Man.
Have settled on an offroad gokart as the baseline vehicle but have come
up blank in terms of ideas for what to do that's visually interesting in
daylight and at night (nighttime runs will be augmented by EL wire from
coolneon.com). I've put a page where I'll post progress at:
www.nmpproducts.com/artcar.htm
--Suggestions welcome!