Today's Big Picture is an arena game that was at the 2003 Dragonmeet Convention. It was basically a D&D (3.5 at the time) combat game with pre-made gladiator's and some basic scenarios. The arena itself was made from styrene and plasticard and added plenty of atmosphere to what was a simple game idea.
EM4 Miniatures also did an arena game with a set of pre painted gladiators and a fold out arena sheet. I'll try and dig out the rules for a quick game session in the next week or so and write up a review.