Just having a peek at Cory's very beta Facebook virtual world named Cloud Party.

It has a lot up and running already, but at this time the aesthetics make me cringe. I'm sure that will change - very early days yet. It uses a cell phone look to anchor visitors quickly and give them something they are familiar with as an access point to everything. Floating islands (reminds me of There a bit, and a few other VRs) are as close as a click, and the reward for completing the tutorials is a modern house. Building using prims is a big part, as well as mesh. Scripting, physics, and so on. Not sure how a noobie would fare as I'm so familiar with VR, but I think quite well. It has been easy so far for me, but then... I did somehow shrink my window and relogged to fix it; after that I was a cloud.