I have created so much stuff in LBP's create mode that I don't even remember most of them. My best project is one that I am working on with a friend. It is a Left 4 Dead-esque zombie killer with advanced zombies, utilizing the Sackbots and Creatinator. Sackbots are, well Sackboys (or girls) with robotic programming built into them. The creatinator is a Helmet with a shooter at the end of it, which can shoot virtually anything that will fit, be it a bullet or a train.
The first part is (imo) awesome, but we have started the second part and just kind of left it on hiatus for about a month. I want to get back to working on it. When we finally publish the first part, probably this weekend or the next, I will post the name so those of you with a Playstation 3 and LBP2 can go play it if you desire.
So back to the game, there are so many things you can do with it. Don't pass it off as a kid's game. Seriously, try it, if you have an imagination and you are creative, this game will be so fun, and not as mindless as (dare I say it?) a shooter.