Arena is an online competition environment for General Game Playing. On each "cycle", it selects a game at random from its game repository, and it selects players at random from its roster of available players. If there are enough available players for the chosen game, its runs a match and records the results in its database. Otherwise, it waits a minute and tries again with another randomly selected game.

The homepage has links to games, registered players, and matches that have been played in the last year. There is also a link to a leaderboard.

Clicking on the Games link shows a table of games. Clicking on the link for a game leads to a page with a brief description of the game in English and buttons for various operations. Clicking on the Rulesheet button shows the games rules in GDL. Clicking on the Stylesheet button shows its Javascript stylesheet. Clicking on Show Matches shows a table of all matches of that game. Clicking on Play a Match allows you to play the game manually. Clicking on Manage a Match allows you to start a match between automated players of your choice.

Clicking on the Players link on the home page shows a table of all registered players, with an IP address for each player, an email contact for the player, and an indication of its status (Offline or Available).

Clicking on the Matches link shows a table of matches that have been played in the last year. You can filter the results by game or team. Clicking on a match identifier brings up detailed information about the match. And clicking the View Match button on this page allows you to visualize the match step by step.

Clicking on Leaderboard shows the relative performance of all registered players. The drop-down list at the top allows you to select a particular game set. The resulting table shows the performance of each registered player on all games in that game set. The unparenthesized number in each cell represent the adjusted score of the player and game corresponding to that cell. (Adjusted score is average score on the game multiplied by n/(n+1), where n is the number of matches played by the player. This factor gives higher weight to the scores of players who have played many matches of each game.) The parenthesized number in each cell gives the number of matches the player has played. The Average column shows the players average over all games in the game set. Clicking on a column head reorders the table by the entries in that column.

Clicking on the image in the upper left corner on any of these pages takes you back to the home page. And clicking on the name of your team (when logged in) shows a page of information about your player.

Arena is open to everyone taking CS227B, Stanford's course on General Game Playing. If you are registered for the course, your team account on Arena is the same as your account on the GGP website. First, start your player. Then go to the Arena page and log in (if you are not already logged in). Go to your account page (by clicking on your team name in the upper right hand corner of most pages). Click the Toggle button to switch from Offline status to Available. Arena will then add your player to its roster of available players. When you want to leave, press the ogle button once again to change your player's status back to Offline. Do this *before* shutting your player down. Also, be sure that your player is not currently in the midst of a match.