Recently the twins have decided they are hilarious. One of them will do something, like throw a chicken nugget on the ground or say "Ruff Ruff" like a dog, and the other twin will chortle like its the most hysterical thing he's ever seen.
I can't tell you how happy it makes me to see them enjoy each other so much.
P.S. Another favorite is hearing Maggie introduce herself to them every morning. "Hi brudder. I your sister, Maggie. Your big sister. You love me?" They do, Mags.