Wow, or we can get someone to make a WoW private server and call it Earthhland Realms, you can use Navicat to edit the item names and stats. You can download DJ eXecute or SH3 (Shadow Hunters Repack), I have my own private server devoted to WoW gamers, the only bad thing is Navicat doesn't work on my computer, I'd be willing to help people who will make one. Also if you want a custom game with custom graphics in 2d, I suggest Eclipse (touchofdeathproductions.com), but 3d, I haven't heard of any good free engines, the pay ones seem nice but it'd take a large team to create ANY game in less than 1 year.
anybody who likes World of Warcaft, go to Runescape.com it is free and is awesome I used to play but lots of it is for members only you can be member for $5 a month