I was not sure where to put this. It is not really a tactical problem, (though of course it's based on it) so I couldn't put it in a tactic thread.. Decided to create a new one.
This game was played a couple years ago. I really needed a win in order to fight for first places in this quite strong Open tournament, so I went all out playing with black. It didn't work out too well, and my opponent took the initiative and, as he admitted after the game, he thought that the resulting position was completely winning for him.. But while calculating the line that led to this position I realized, that there is this witty move that saves black.. Find it!
As you see, black's position looks quite tough. White has a lot of pressure on queen side, it is tough for black to get his queen side pieces in to play, and attack seems to have died. However, there is a move that leads to a perfectly playable position (maybe even a slight edge) for black.
***NOTE***
This is not a forced win. White has a lot of replies after the move made in the game, so do not try to calculate them all. Just try to find a move that improves black's position dramatically. I would rate this as a quite hard one, probably for players of 2100+ or so.. It does not mean that lower rated players cannot try though - give me your best shot!