Awesome. I was there in 2006 when this project got off the ground. If I remember correctly, it was a fork of TuxKart, since the author could not be reached in order to take over the project (or they didn't want to hand over maintenance).
It was a part of the Linux Game Tome forums Game of the Month. I think there were really only ever two - SuperTux and SuperTuxKart. The idea behind GotM was to get devs and artists to all focus on one game to make some improvements. In reality, people got attached and never moved on the the next project. I still think it was a success, though!