From my partner, Chris Wand, describing a program one of his companies put in place over the holiday to encourage employees to clear a bunch of outstanding bugs in their backlog:
Anyone that wanted to fix a bug during their holiday break could earn $50/$75/$100 (depending on the severity of the bug) for each known bug they fixed (the catch was that QA had to approve the fix). The person that fixed the most bugs also earned an additional bonus (I think it was $500). They managed to clear about 100 bugs off their list… It was so successful, they’re thinking of implementing it at other times (i.e. over a long weekend, etc.—of course making sure that they don’t set it up so people are working on the bug fixes during normal working hours).