ways to practice a guitar with out a guitar.....?

i just moved out to California from Florida and i love to play guitar
but i left mine in Florida =C .anyways i'm getting a guitar out here
soon but i wanna stay "warm" and don't tell me guitar is like riding a
bike.. cuz its not u CAN get worse.

something i've heard is rolling a quarter through your fingers is that
one way??

any who please give me some tips!
thanks

oh and don't say air guitar lol i do that everywhere anyways i look
like a retard ... but its fun.