LOW HANGING FRUIT
I'm fond of the "now or never" school of fixing bugs. Either it's important enough to fix it now, or you'll never get to it. However, I like to have a "low hanging fruit" (or "LHF") column for those bugs that really are just a quick fix (eg: less than 15 minutes, definitely no more than 1 hour) and would have a noticeable impact on the quality of the app. If someone has a spare moment they can grab something from this column, fix it, and have a disproportionate impact on the perceived quality of the app.