I'm tired of these White to play and win diagrams so here's something different. This was an OTB game I played yesterday as Black against a 1700+.
How did I blunder? Many guesses welcome! The one who guesses correctly gets a street legal Ferrari Enzo.
BTW: Note, that the move must still have some logic. Don't say something like Qxd5. 😛 Moreover, it doesn't completely throw away the game, it just hands White the advantage.