Creatorverse, Linden Lab's iPad sandbox building game, now comes with a boatload of tutorials on YouTube which illustrate just how inventive you can get with the thing. Take this one on giving Creatorverse balls physics properties:
Pretty impressive, and there are many more here, showing you how to build wheels that work and teleporters that, well, teleport, and so forth and suchlike. Far as I can tell, the game's site isn't featuring user-created Creatorverse content yet, and I can't find any user-generated videos on YouTube, and when (if?) we start to see both, that's when the real fun begins.