I'm trying Blocksworld with my GF :). It's very similar to Roblox and it's made by Linden Labs (the peeps that brought you Second Life) It is very fun because you have this coding blocks (like in Game Maker) to bring your creations to life and make your own games. The editor is also very easy to use. The controls are kinda hard, I'm not gonna lie but I think its worth checking out :).