It doesn't take long for your inner child to emerge when you're splish-splashing around a swimming pool under the hot sun, but if your pool party's guests are all adults, games such as "Marco Polo" won't necessarily please the guests. Instead, put together a fresh list of games for adults that combine fun with just a little competition.
Provided you're enjoying alcohol responsibly, grab a few plastic cups and use some ping-pong balls for a twist on the traditional party game of beer pong. Your "pool pong" game needs a floating raft on which to carefully balance the empty cups. Then, divide your group of adults into teams; let the raft float between the teams and take turns tossing the ball toward the cups. Make the losing team hop out of the pool and top up the drinks of those on the winning team.
Guests who are avid or casual athletes will enjoy sports-themed pool games, so they can keep cool while playing. The accessories you buy don't have to be elaborate. A volleyball net and ball make for hours of fun, while a pair of goals and an inflatable ball serve as all the equipment you need for water polo or handball. One or two basketball nets mounted to the pool deck give your party guests a chance to show off their most creative dunks in a game of hoops.
For a party in which most of the guests have competitive streaks, games such as the noodle joust provide ample entertainment. Each competitor holds a foam noodle and sits on an inflatable object. The goal of the game is to knock your competitor into the water in a game that mimics traditional jousting with a horse and lance. Up the ante by making the loser of each round tread water for a few minutes. As an added challenge, have the two competitors share the same raft.
A plastic soda bottle, with the label removed, serves as the focal point for the "invisi-bottle" game. Fill the bottle with water, have your guests sit around the edge of the pool with their eyes closed and toss the bottle into the center of the pool. Upon hearing the splash, everyone must dive toward the bottom and look for the bottle; the issue is that the bottle's transparency, mixed with the mass of bodies, makes it tough to find. The first person to find the bottle gets to throw it for the next round.