Memories
Since graduating from high school means the graduate is taking the next step in her life, she will probably want to reminisce about the past four years with friends. Surprise the graduate with a white T-shirt and have the party guests sign it.
You can also play a time capsule game by having the guests write decorative notes and make trinkets out of craft supplies, and then vote on which mementos best represent the graduate's high school years. The winners go into the time capsule.
Inside Party Games
If the party is indoors, you'll have to plan your games accordingly. A great indoor game that can also serve as an icebreaker for guests is to play "guess who." Guests get the name of one of the graduate's teachers taped on their backs, and then mingle with other guests, who give them hints as to which teacher is taped to them. The first person to guess correctly wins.
You can also create a spin on the traditional "pin the tail on the donkey" by using a picture of the high school principal, and instead of a tail, pinning other objects like books, rulers, apples, mustaches, or jewelry on the picture. The person who gets the object closest to where it should logically be while blindfolded wins.
You can also create an original Bingo game by making Bingo cards that have answers to questions about the graduate on them. Call out the questions, and if the Bingo card has the corresponding answer on it, cover that space up. The first person to cover an entire row on the card wins.
Outside Party Games
If you plan on playing some games outside, you can play a much wider variety of games. If you plan on going all out, you can rent party equipment like water slides, inflatable jumping surfaces and even bungee rides for the graduation party that kids, teens and adults alike will enjoy.
If the graduate is an athlete, you may want to play some sports at the party. Games like a basketball shootout, a soccer kick, volleyball and golf are all great choices.
There are also many traditional outdoor games you could play during the party. Horseshoe toss, a water-balloon toss, and footraces are all great games to play outdoors.
If the party will be long, you could also hold a scavenger hunt. Simply make a list of objects to find. Limit it to the party site, or have participants hunt all over town for objects. Scavenger hunts can be completed with individuals or teams. The first person or team to find all of the objects on the list wins.