A Bloody Mary probably isn't to bad for you.

vodka and orange seems like a nice idea.
I'm told that generally, the lighter spirits have less calories then darker ones. And cider has significantly more calories then beer!
Don't forget to drink some water too, to stop yourself from getting dehydrated.

I to used to bartend, what i do when i wanna booze up is drink whiskey on ice, its not full of calories or carbs like beer and a few gets me pretty tuned in

Actually a shot of whiskey(or any spirit for that matter) has the same amount of calories as a bottle of beer.