Have Rocket, Will Travel (1959)

"Hilarious mixture of missiles and mirth!"

The Stooges are janitors working at a space center who accidentally blast off to Venus. They encounter a talking unicorn, a giant fire breathing tarantula, and an alien computer who has destroyed all human life on the planet and creates three evil duplicates of the Stooges. When the boys return home triumphant, they are given a hero's welcome.