Quadra Pair 42
The objective? Complete the puzzle in the fewest of moves possible, of course. Rumor has it that it can be done leaving just 21 in the display. But the tricky part is figuring out how to solve it first.
And I'm not sure what's more impressive about this one: whether it's the fact that even after knowing the 'rules' in the game I am still able to come back to it days later and struggle to solve it again; or, the fact that the entire game was created from scratch with just a couple of hours work. It's an excellent little puzzle game. But be warned: keep a soft pillow nearby; you may need something to hit.