Which two books, movies, or television programmes would be made more entertaining by swapping their cast of characters?

For example, we could use the television programme Star Trek (original series) and the book The Lord of the Rings. Spock, Kirk, McCoy, Uhura, Scotty, and so on would undertake the Fellowship to destroy the One Ring, while Gandalf, Frodo, Pippin, Merriadoc, and co. would command the starship Enterprise on its five year mission. Both would be made more entertaining (in my opinion) by the switch.

“Captain, my tricorder is picking up Ringwraith activity.”
“Set broadswords to stun, Mr. Spock.”

“Gandalf, the Klingons are locking disruptors!”
“Raise shields, Mr. Gimli. They shall not pass!”
“I’LL GIVE THEM A TASTE OF DWARRRRRVEN PHASERRRS!”

What are your suggestions?