Dofus is a flash-based, browser fantasy game. It says it works on all platforms, and will even play over a dial-up modem, and there's no reason it shouldn't as long as you've got flash installed. It worked without a hitch (once I'd set Flash permissions to run the download) on my Mac. It offers an extensive free-to-play area, although some skills are limited unless you pay - the UK servers charge £6.70/month, (about €10 or US$14), and there are a couple of pay-to-play character classes too.
Creating characters is fairly easy, but the support from the main site is poor, although the Dofus wiki can help if you choose a popular class. There is a "total beginner" area where you get shown the basics of combat, then a newbie's area you can explore - although there are some really tough fights there if you're not careful. I expected to have a quick look, and move on. I'm not sure I'm hooked, but I stayed long enough to handle the final dungeon and get my stylish hat (it makes you do +1 damage, sounds good to me!).