Every house built in the last 40 years has typical 4 foot wide closets with a set of 48" bi- fold doors. This is a pictorial display of how to turn one of these into a fully functional bar with minimal disruption to your house and no drywall dust.
Step 1: Remove The Doors
Carefully take off the doors and all hardware. Leave the trim mouldings. You should pull out the interior shelf, shelf support and closet rod. The interior should be drywalled and painted already. You'll have to fill and prime any holes where the door and shelf hardware were fastened. (OK,I lied, you'll have a bit of drywall dust.) The distance between the door frames should be 48" or close to it, of course, you checked that before you started.