Jobe Makar: A* (astar) Pathfinding
A* is a state change optimization algorithm. It looks at a system in its current state and determines the lowest cost series of state changes needed to arrive at a target end state. Most commonly A* is used for pathfinding. I have never seen A* used for anything but pathfinding, but you could use it to do things like solve a Rubik’s cube or a picture slider puzzle.
A nice implementation of A_STAR in actionscript