It happened a while ago, but Wired covers the 2007 Regolith Excavation Challenge.
One commentator summarizes the spirit of the challenge, saying, "We think of it as DIY punk rock meets high tech".
This paragraph from the article gives insight into the motivations of some of the challengers for this and other similar prizes:
"Why devote your spare time — and garage space — to gathering moondust? "Money and pride," says Geoffrey Pulk, the Michigan engineer. "I watched a couple of the other competitions." He's talking about previous NASA contests that solicited designs for a space elevator-climber and a lunar lander. "I thought, ‘I can do this,'" Pulk adds."
The article also has a bizarre picture of a clearly do-it-yourself, garage-made regolith excavator, or cookie assembly line, or something like that.