What makes this story funny is the off the wall characters, throw in some crude sex jokes, senior citezans enough weed to challenge Cheech and Chong, and a monkey that knows Karate, and the movie has you laughing hysterically.
Linda Cardellini has just gotten a job as his boss. Plot ensues. Alex smokes a lot of pot, gets Linda to smoke a lot of pot, and then finally gets his grandma smoking pot too. Somewhere in there Grandma's Boy becomes a lot of fun. . A little absurdist pothead humor never hurt anyone. Just ask Harold and Kumar.
Some of the other off the wall characters you will see in this flick is a Witch Doctor, a Home Grower drug dealer who wants a collection of animals. An egotistical video game tester who dress like Neo from the Matrix and talks like a robot when he gets nervous, and an out of his mind company owner, who is a new age hippy.
Go out and spend your money on this movie its good, im giving it a 5!