Go offsite to M.I.T.'s "Scratch" educational project, where they have a collection of tessellation animations written in a programming language designed for kid students between 8 and 14 years old.
Go offsite to YouTube, to see an iPod/iPhone application called "CirCull". That word's a portmanteau / mash-up word the author invented by combining "circle" with "cull". It's a tessellation game in which you tap adjoining tiles to switch their places. Whenever three adjoining tiles have the same color, your points go up and the tiles disappear. That disappearing is the "cull" in "CirCull". The 2D tessellation plane has been heavily distorted by a fisheye view-- that's the "circle" in "CirCull". The fish-eye lens makes the 2D tessellations look a bit like a circle-limit tessellation.