There is a level in the game near the end, I forget which one exactly, but you'll notice how you build this sort of wooden stand thing which will keep breaking if one of your characters stands on it. I just built it, jumped on it, and repeated it for about 150 times.
I also want to point something out about KungFuStu72's review. Some people don't want to play every level at least twice and even if you played the whole game twice, you still wouldn't build 250 lego build it's. If I had about 100 lego build it's after the first playthrough until I noticed the build it that kept breaking.