The Center for Modern Rationality is now offering prizes for suggested exercises:

$50 for each exercise promising enough that we test it during a Saturday session. A $500 prize for any exercise which actually seems to work (as in, we decide to adopt it into the unit after testing).

Hmm. I'd understood that there was some pretty convincing evidence that offering cash incentives like this is counterproductive - it decreases creativity and effectiveness of troubleshooting. I don't have scholarly cites handy (I know there was a CMU/LSE study) but this is popularised in Dan Pink's "Drive". (There's a TED talk and a great RSAnimate video on this.)