Once it's too cold to kitesurf in the water, it's time to find a frozen lake and kite on top of the water. Build a "traditional" Polynesian ice canoe using aluminum extrusion or whatever material you have at hand. If the water ever froze in Polynesia, I'm sure this is what their ice kite/sail craft would look like.
Initially, I cut some ice skates out of steel, sharpened them on a belt sander, and bolted them onto Saul's old sand buggy. This ice buggy moved fast, but I felt like I was always being pulled out of the seat by the kite.