You can see Beta 2.1 running on Shadows:
http://www.shadowsofnamek.com/forum/proarcade.php
You'll notice the reduced query count on the main arcade page, as well as some minor bug fixes that had been bothering people.
The bare minimum, SQL-wise, is one query per game. With a large score table, there is already quite a bit of PHP going on to process all the scores that come from those queries. However, I am thinking of testing another version that just does one query for ALL of the games/scores and then processes it via PHP.
When I went from the multiple queries to all PHP, the page load time actually increased, but the number of queries dropped dramatically.