Since a few people have expressed interest
Sheldon of the Lens: Big Bang Theory / Lensman Series crossover. Gen. Humour. One of the Kinnison sisters shows up from the future to recruit Sheldon for a starkly incredible quest to save three galaxies. Meanwhile, Leonard just wants to get some sleep.
This Is (Not) America: Supernatural / Life On Mars crossover. Gen. Humour. Someone said 'Sam and Dean' to me, I misheard it as 'Sam and Gene' and this is the result. Sam and Dean swap places with Sam and Gene, and everyone is confused. Spoilers for Season Five of Supernatural.