ONVERSE!it is the best virtual world sign up here
Smallworlds is probably the best, you can become a member by earning gold, which you can get for signing up on a website or doing a survey! You can also use magic and ride on hoverboards to magic...
Fantage Poptropica Some of the Facebook games
Onverse is a good choice!
Try Marapets: flash games, fully customizable characters, quests, missions, item/pet trading, battles, fashion contests, giveaways, prizes, tons of free stuff, friends, forums, chat, blogs, clubs,...