David Arquette sunglasses bike dancing with the stars ride

David Arquette is all about fitness as a Dancing With The Stars contestant!

He rode his bike to and from rehearsal on Sunday, where David and partner Kym Johnson, along with the other contestants, practiced for this week's '80s theme!

Arquette and Johnson are doing an '80s-inspired tango! Check out the pic below that David posted to his Facebook page -- he's ready!

We also caught up with Nancy Grace at rehearsal ... and she had a suspicious stain on her shirt -- see the pic after the jump!