Day 11: Funniest episode
I would say, Closing Time, episode 12, season 6. Partially because it has the return of Craig, and I not only love the character, but I'm falling in love with the actor, James Corden.
Why is it my funniest? Well, there's James Corden,
Stormageddon Dark Lord of All,
a silver rat thing,
and confusion abounding.
It is the awesome sauce. Go watch it. You might want to watch The Lodger from season 5 first. It's also funny, but I find Closing Time funnier.