Are there any free virtual worlds

Try Xivio.com, its a free 3D virtual world! No download too!
VirtualFamilyKingdom.com is also free and is a cool 3d virtual world, and no downloads.
ClubPenguin.com is kind of 3d
Dizzywood.com is nice and 3d
Moshimonster.com
Whyville.com