Once Aidan showed mommy and daddy that he could pull himself up without them we had to change some of his sleeping arrangements. The mobile he loves so much had to come down before he turned it into a trapeze. His mattress pad which was at a nice, comfortable, mommy daddy height had to be lowered. I had visions of him side hopping the rail and wreaking havoc whilst we slept in ignorant bliss. Now his mattress is lowered all the way down. We thought that was the fix since, to this point, he's only stood up when he could grab something horizontal. 

Shortly after we put him down tonight we heard some pretty standard "I don't think I want to be up here" screaming. When Jaime opened his door she found him standing in the crib, holding the vertical bars and chanting "Attica!" Clearly this means the only option is to chain him down. I'll stop at Home Depot on the way home tomorrow.