Rolling pin

 is a Melee weapon that can be found in the Capital Wasteland and Point Lookout.

Tranquility Lane version
A special version exists in the simulation Tranquility Lane, with significantly higher damage. It is found on the kitchen table in the Rockwell Residence.

Killing anyone in Tranquility Lane is temporary, as talking to Betty will reset them until you activate the Chinese invasion simulator, then they are dead for good.

Locations

 * In the Taft Tunnels not too far from the last door with the Brotherhood of Steel guard on a table near a plush chair.
 * In Mama Dolce's Food Distribution, top floor on a desk near Mama Dolce's Loading Yard door.
 * Found in various containers in the Capital Wasteland as a leveled item; although more plentiful in Point Lookout containers.