Okay, so I've been re-watching Firefly, and I just finished watching the episode "Safe". In case you don't remember, that's the one where Shepherd Book gets shot while Mal tries to sell some cows, Simon and River get kidnapped by hillfolk, and the hillfolk try to burn River at the stake for being a witch. There's lots of flashbacks to when Simon is younger- Simon and River as kids, Simon realizing his sister's in trouble and his parents not listening, Simon getting bailed out of jail by his angry dad.
So, in the scene where Simon and River are kids, and they're playing Alliance vs Independents (the Independents outflanked them with dinosaurs, they've lost their supplies and now must cannibalize the men)- guess who plays Young Simon?
ZAC EFRON. BABY ZAC EFRON.
I totally didn't recognize him, he's so little and cute. I just happened to see his name in the credits and was like IJKEIUQLKAIGHZWHAT?!!