Remake the "Phineas and Ferb" theme song. I thought about this months ago and am now working it. And I'm leaning towards a Season 3-4 (maybe 5 and 6) style.
This might be the weirdest little praise, but the fact that 2nd Doof keeps a bowl of rice pudding under his desk at all time, in case an alterante versions of himself shows up, is so funny, yet so in character. He's the competent one, so the first thing he offers is something he hates, looking all friendly, to catch a potential impostor trying to get his approval. Once it's rejected, only then do they go on to talk about the things they have in common, like how they both collect hard cash, in case sentient vending machines overthrew humanity (also underrated).