I counter HuskyHog's list list of free MMOs with, not a list, but THE best free online browser game.

I bring to you Kingdom of Loathing. It's clever, fun, hilarious, ACTION packed. Screw 3D, that's last gen, along with rumble. This game is only for the hardcore. It's only text and 6kb gifs, with a side of awesome.

Basically besides being great, it's an RPG. And the stats? Strength? Intelligence? Constitution? pfft! what ever the means. The stats are Muscle, Mysticality, and Moxie. It's got classes, but no lame wizards and warriors. I'm talkin Pastmancers, Seal Clubbers, Disco Bandits, Accordion Thieves, Turle Tamers, and Saucerors, each with there own skills, attacks, equipment, etc. Fuck dollars and cents, the currency is meat, and chow mein and penguin skins are commonly traded. While adventuring, you encounter such fiends as the Bonerdagon and filthy hippies, INTENSE

Its got an awesome community. People are always willing to trade, sell, give advice, and set up several events happen outside of the game and more. The man who started it all, Jick, is always communicating with the 200,000+ active players, taking suggestions, and updating the game every tuesday. Jick records a podcast at least once a week sometimes twice where he talks about what he's updating and reads player suggestions with the games writer, MrSkullhead.

This ain't no Ron Workman game where you "just blow shit up", so if you lookin for that, don't try it. I've been playing for a little over 2 years on and off, and I'm still not bored of it. If enough Dtoiders join up, I'll gladly pay to start a clan, and I'll help anyone that needs help. Remember, an adventurer is you! in the Kingdom of Loathing.

[I made a little forum post about it here]