I happened upon this video of three of the cast members of the current TV show The Flash singing a “gospel version” of the Firefly theme song. Left to right they are Jesse L. Martin, Carlos Valdes, and Rick Cosnett.
Valdes plays a character named Cisco who makes tons of references to cult/geeky things, so it’s very fitting that he’s one of the ones in the video. My favorite Easter Eggs on The Flash have been the extra-meta references to the TV show The Big Bang Theory. Anyone who watches that knows that Sheldon is a huge fan of the character The Flash and that he often wears T-shirts that somehow reference him.
Here is Cisco on the TV show The Flash wearing T-shirts that reference The Big Bang Theory character of Sheldon. (If you can’t make it out, the first one says “Bazinga!”)