For a large prize, you can get a small amount of experts to work for a long time on something straightforward but technically demanding. For a smaller scale, f

For a large prize, you can get a small amount of experts to work for a long time on something straightforward but technically demanding. For a smaller scale, flip everything. Get a large amount of dabblers to work for a shorter time on something that might be hard to quantify but is not really hard to do. So maybe you should reward inspiration that has just enough execution. That is, enough that people get it and it will sustain the project, but not too little that someone would have done it without the prize. Now, I'd say get some more specific goals than "nifty" because otherwise we're all going to say "libraries for Arc" which is nifty to us but maybe not yourself. Plus if you pick some criteria that inspire people, are clever and/or people really get behind, you can get a lot more exposure, which will increase the expected quality of the winner. And then maybe you can hit up some people at Community Next or something to add to the prize pool. But if you really do want merely nifty, you could just set up a restricted subreddit for judging... although I'm sure I didn't have to tell you that!