My interpretation of the theme led me to a puzzle theme. I have made platform, shooters, pac-man-like and 3d games, but  I never made a puzzle game before. The experience was better that I could think.

http://www.ludumdare.com/compo/ludum-dare-27/?action=preview&uid=24602

Now I’m getting fun playing the other games. And I surprised that I found no one other puzzle! Maybe this is the most uncommon game category?