Yes, you definitely want to know about closures.

The interesting thing about closures is that you hear about them and wonder what they could possibly be good for. Then you run across someone who is using them and you wonder how they thought up the crazy stuff they are doing. Then a switch goes off somewhere inside and you suddenly have no trouble figuring out interesting things to do with them.

So hopefully you have now heard about them and are wondering what they could possibly be good for. Well now try this, that, or the solution I threw together for 5x5 Puzzle for some samples to move you to the next stage...