Pun is changing of words of two meanings to make the sentence humorous. The example i chose is a cartoon were a guys says vacuum cleaners "suck" in were he is saying they are bad, and saying that they suck in dirt.
Irony is the opposite of what is expected to happened. The example I chose for irony is a man (xzibit) is calling a cat "dog" which many people call each other to represent that they are friends.
When slapstick comedy is mentioned the first image I think of is the Movies Home Alone. Home Alone is a perfect example of slapstick humor because the little boy is constantly injuring the two robbers trying to get in the house.