Dungeon Fighter Online is a side-scroller beat-'em up game (Think Castle Crashers or Double Dragon) with an MMO flavor. It's free unless you want to buy continues (which you honestly don't need if you're in a good party) or cosmetic items, so it's awesome.
Here's a link to the Getting started page. How to install, getting an account for the game, some in-game basics, etc.
Here's a link to The Different Character Classes you can pick. Oh, and you can have up to eight characters.
Here's a link right to the downloader, if you think you can figure everything out on your own.
Have fun~
