There's a lot of pleasure in being an adult and watching children have fun. But what about having fun yourself? Adults rightly put it upon themselves to work and provide, but often they neglect their own need to enrich their lives with activities not directly related to their career or responsibility. Adults shouldn't be afraid to do a little something for themselves---they might end up enjoying it.
Do Something You've Always Wanted To Do
Once adults graduate college, their opportunities to learn tend to taper off. But being an adult with a job means you have far more disposable income than you did during your wild and experimental younger years, and therefore you have the means to try something new. Buy a really nice guitar and take lessons. Join a bowling league (couples bowling leagues can be particularly fun), learn to kayak, learn to dance or play softball.
Quit Being An Adult For A While
Just because you grew up doesn't mean you have to quit miniature golfing altogether. Once in a while, it can be great fun to do teenage type activities. So go to the arcade and play some Skee Ball. All around the country, adults are playing organized versions of popular playground games, especially Kickball and Capture The Flag. Remember how fun those games were when you were seven? They're still that fun. Also in chapters around the country are groups dedicated to geocaching, or looking for hidden packages through the use of navigation and technology. These treasure hunts are a huge cult hit, and can be quite a lot of fun.
Do Something You Never Thought You Could Do
When you were in school, you were constantly introduced to new challenges. Adulthood is no reason to flatten your learning curve. If you're rotten with computers, take a beginner computer class. If you can't cook, take a cooking class. And if you don't know your way around a car, take a class in basic mechanics (that one in particular can save you a fortune in minor car repairs, and it can help you sniff out a dishonest mechanic.)
Get Serious About Fitness
Getting in shape can be a fun and fulfilling challenge; you can feel younger, you can look better and you can get hooked on your ability to surprise yourself. Train for a 5K. Train for a 10K. Train for a marathon; you won't be the first person to try it at age 30, or age 40 or age 50.
Get a Crafty Hobby
It used to be that things like woodworking were the bane of retirees. But you don't need to look at things this way. There is satisfaction in making something of nothing.