more fun than a barrel of monkeys

Very amusing or diverting, as in That video game was more fun than a barrel of monkeys. This expression, first recorded in 1895, alludes to the playful behavior of these primates.

The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.