barrel of fun 

A wooden-like barrel that produces pleasurable vibrations to anyone who deposits $0.50. The vibrating element is arranged in such a way to imply that the vibration is for feet.

Proper use of the Barrel of Fun requires the rider to sit on the vibrating element.

The Barrel of Fun is especially pleasurable to those of the female sex.

Ralph: Roxanne, you seem to be enjoying that Barrel of Fun a little too much.

Roxanne: I am just getting primed for later when we get back to the Roxy room.

barrel of fun by Violated Centaur March 12, 2005

more fun than a barrel of monkeys 

a very good time(from the the name of a toy consisting of a plastic barrel filled with flat plastic monkeys that can be hung by each others curved arms)

That dance was more fun than a barrel of monkeys

more fun than a barrel of monkeys by The Return of Light Joker December 17, 2007

Barrels of Fun 

Something incredibly fun!

That was totally barrels of fun!

Barrels of Fun by That Guy Who Does The Stuff September 5, 2014