Keep things light at a 50th birthday party by putting on a skit that gently pokes fun at the guest of honour while letting him know how much you love him. Pick a few friends who are not afraid of performing to help you write and put up the skits. It may be best to limit the number of skits at the party to one or two, so that guests don't get bored.
Have a performer hide somewhere out of site. You want to be able to hear him, though. Introduce the skit by explaining to the guests that the party's location echoes a lot, which you find strange. Ask another performer to come up and demonstrate. Before the skit, instruct the performer to shout "Hello!" first. The hidden performer should echo her by saying "Hello. Hello. Hello." Next, have her yell out something mildly inappropriate, but that won't offend the guests, such as "over the hill!" or "look who's 50!". Gently chastise her and tell her to try saying "Happy Birthday!" After she yells "Happy Birthday," the hidden performer should instead repeat the original inappropriate thing.
A Day In the Life Skit
Come up with a skit that depicts a typical day of the birthday person, whether at work, home or where ever most guests know her from. The skit should be in two parts: before she turned 50 and after. Have the person playing the guest of honour act normal during the before skit, then completely silly during the after skit. You may even want to have two performers to play the birthday person before and after. Remember to keep your teasing gentle and don't do anything that will hit a nerve.
Favourite Story Skit
Everyone has a favourite story. Find out what the guest of honor's favourite is, then write a truncated version of it in skit form. Make sure you somehow manage to fit the birthday person into the story, either in place of the main character or as the main character's new sidekick.
Enlist the help of the birthday person's children, grandchildren, nieces or nephews in coming up with a skit. You can pick and choose choice moments from the guest of honor's life and have the children act out those moments.
Struggle Over the Hill Skit
Cut out a hill from a piece of poster board. Make a small finger puppet of the guest of honour. Place the finger puppet on your finger and begin to tell the person's story, starting at the bottom of the hill. Every ten years or so, advance up the hill, so that you reach the top when you get to age 50. Have the puppet teeter at the top of the hill, surveying his surroundings and thinking how life can't get much better. You can end the skit there, on a positive note or have the puppet plummet down the other side.