A month ago we finished our first Icehouse/Treehouse game called Pyramids and Flags.
Pyramids and Flags is a game for 2 to 4 players.You need one Rainbow and one Xeno set of Treehouse pyramids to play it. Out of these pyramids, players put together flags of specific countries from all over the world so you need also goal-cards with flags. Apart from the pyramids and goal cards, you do not need anything else.
For more: http://www.icehousegames.org/wiki/index.php?title=Flags