Outdoor Games with Friends
There is nothing quite like a day spent outside to exercise the imagination of a 12-year-old. If it is summer, organize a picnic with a bunch of friends and go to the park. Play games all day, such as Capture the Flag, Tag, What Time Is it, Mr. Wolf? or Hide and Seek. If there is wintry weather, don't bring food, but organize a giant castle-building activity in the park. Make sure it is a day with perfect packing snow, and get cracking. Your day might even end with a giant snowball fight with friends.
Movies
It may seem obvious, but movies are still a top fun thing to do. Going to a theater is a nice way to keep cool on a hot summer's day, and a good indoor activity in the dead of winter. Find a movie that you and your friends want to see and ask a parent to accompany you. Alternatively, you can have a movie party at your house. Rent some DVDs of your favorite movies and ask a few friends to come over for the evening. If you ask your parents nicely, they might even order pizza for you and your friends.
Museums
You might think that a museum is the least fun place to spend your free time. But museums have a lot more to offer than boring education. Look for exhibits that feature topics that interest you, such as insects, dinosaurs or cutting-edge technology. Museums sometimes host technology exhibits that allow you to try out gadgets that seem futuristic. In addition, many museums offer free or very cheap admission for kids.
Arcade or Entertainment Complex
You'll have to be very nice to your parents if they agree to take you and your friends to an arcade or entertainment complex. You'll get to spend the afternoon playing video games, air hockey and hoops. Some complexes even have fun batting cages or skiing and skateboarding games. If you are at an arcade that gives tickets redeemable for prizes, pool all your tickets together with your friends. You might be able to get a giant jar of candy at the end of the day.