I've always had simple tastes, and I'm fortunate to have married my match.
When I was young, I spent my money on baseball cards, pinball and candy. When I was a little older (12-23) I spent my money on music, concerts and the accoutrements. From 17 to 32 I spent my money on travel.
Recently, I've been spending money on toys. I take my kids to the park whenever we get a chance, and I bring a huge bag of toys for all the park kids to play with. I bring a good snakeboard (currently the most popular toy), badminton for four (half the time it's too windy), about 20 balls including baseballs, softball, three gloves; bubble making kit, half a dozen jump ropes inclusing a very long one, juggling balls, balloons, scooter, hula hoops, big wheels, four Frisbees, little helicopers, yoyos. And then there are the bikes and other big things that we sometimes bring just for variety. These toys have actually been a very cheap investment. I have to continually replace lost or broken crap, but the neighbors really appreciate it, and I get plenty of exercise that's more fun than the gym (or even hiking?).
I wish I could find a pogo stick strong enough for adults (I want to go on it, too). Some stilts would be cool, but I do have concerns about broken kiddie bones and the ensuing lawsuits.