Only You is the one that got me. Not because it's tremendously different from other puzzle games of that type, but because of what he manages to convey in the tiny, tiny space allocated--it's not just a puzzle game, you're matching up loving couples. (In an abstract 5 kilobyte sense.) Other good choices are Game Theory or Ten Ten. You'll need a Commodore VIC-20 emulator in order to play them, though.