We will follow these rules: http://robogames.net/rules/all-sumo.php
Double elimination tournament
The ring we will use is made of MDF painted FLAT BLACK with a GLOSS WHITE border ring. The rubber surface of the last ring was just to hard to source, build, maintain and paint.
Parallax $240 - Comes with 2 bots. Kit works well, but expensive http://www.parallax.com/product/27402 and http://www.amazon.com/Parallax-SumoBot-Competition-Serial-Adapter/dp/B004SRZLZU
Sumovore Mini Sumo $98.50 http://www.solarbotics.com/products/k_sv/
Mark III $92 http://www.junun.org/MarkIII/Store.jsp
Gallery of Sumobots
Nice Bot, but not a Sumo
Another Arduino Sumo
Sumo from Tufts Univ
Thingiverse of above sumo http://www.thingiverse.com/thing:1548
Check this one out http://www.huv.com/miniSumo/seeker2/
And another one http://letsmakerobots.com/node/19648
What about Legos? http://www.nxtprograms.com/mini_sumo/index.html
Please add your own!