EA have launched a Sims 3 demo that will theoretically run in your browser. The demo was announced on the EA site , spotted over on Blue's News, and contains "elements from The Sims 3, The Sims 3 Late Night, The Sims 3 World Adventures."
EA's link doesn't seem to work, but we managed to launch the demo from the Gakai front page , the service providing the streaming tech behind the trial. The demo is time limited to 20 minutes. You'll be able to create a sim and lead them to their a gruesome death in an Egyptian pyramid, a haunted house and a vampire lair. Or you could keep them safe and watch them live long, happy fulfilled lives, but where's the fun in that?