With the apparent demise of Oblivion Online I feel the need to record a list of interesting multiplayer editors.First in the list is a free multiplayer editor of Grand Theft Auto: San Andreas:

Multi Theft Auto (MTA) is an open-source software project that adds full on-line gaming support to Rockstar North’s Grand Theft Auto: San Andreas PC game, in which this functionality is not originally found. It is the first open-source modification that adds a highly customizable network play element to a commercial closed-source single-player PC game.

There is of course still Warcraft III (Mac and PC) and Oblivion (single player) if you wish to try the multiplayer hacks..

April 29 there may be a multiplayer editor for Dante’s Inferno..

Of course if you have a Playstation III there is always little big planet but I don’t know how unlimiting it is. Unlike of course Crysis that is perhaps too umlimiting.

Most of the above include in-game assets, but if that is not required, unity 3D, shiva or perhaps Esperient Creator are options.