This'll be a bit hit'n'run, I'm afraid, but here's a game:Fishing for Complements
Info and download for Windows: http://colthor.co.uk/games/FishingForComplements.html
Catch, reel in and bring to shore the object you need to make the shape in the bottom-left whole.
It's fairly rough and ready (and looks/sounds it; artistic talent is a thing other people have), but only took about five days out of an eleven day period. A couple of extra days' fiddling could probably make it a better game, but I won't have the time for a week or two, and the central mechanic works (I think) quite nicely, so here it is.
It's C++ using DirectX and OpenAL. You can find a few other games I've made for 1 Game A Month here