A favorite of mine; back when I frequented a lot of software conventions I would bring my set and those odd, colorful pyramids would always draw some attention.

You can tell the difference between developers who play this game, as opposed to more "ordinary" people in that they approach the game differently. Developers come up with rules like "The sum of the pips pointing at other pieces is even." A new player in the latter group came up with one of my favorite Koans of all time: "One piece is highest."