As mentioned previously, I taught myself how to juggle.
And you can, too! All you need is three tennis balls and, at the most, an hour a day.
Begin with two balls, one in each hand. Since I’m a righty, we’ll start with that assumption.
Throw the ball in your right hand in an arc, with an apex not much higher than your own height, to your left hand. Make it high enough that you can see where it’s going but low enough so that you don’t have to wait for it. Watch it in the air.
When it starts to fall, throw the ball in your left hand, in a similar arc, to your right hand. The rising left-hand ball should pass inside of the falling right-hand ball.
Catch the right-hand ball in your left hand. The left-hand ball should be, roughly, at the apex of the arc. When it comes down, catch the left-hand ball in your right hand.
Repeat this until it is fluid. After a number of successful throws and catches in this manner, you should be able to memorize the strength and motion needed to float the balls from one hand to another. Remember, "Throw then catch!"
Once you have a somewhat fluid motion from right to left, try it from left to right.
For a related exercise, try two balls in one hand. This helps your timing and throwing immensely; if you can get a handful of catches one-handed, you can confidently juggle three balls.
When the two-ball method is memorized, add in the third ball.
With two balls in your right hand (one in the left), throw one of the two balls to the left hand. Throw/catch with the left hand, then try to throw/catch with the right hand. Catch the free ball in your left hand, then stop.
Do it again. And again. And again. Then switch your starting hand and do the whole three-catch exercise from the beginning.
When you’re comfortable with three catches, go for four.
Lather, rinse, repeat.
Then move up to five catches.
By now, you should be able to go for more. When you’ve got free time, see how many catches you can get in a row.
Within three days of teaching myself how to juggle I was nailing a couple of hundred catches regularly.
Within a week of starting, I could do a couple of thousand catches while carrying on a heated and in-depth conversation with several people.
It won’t make you a living, unless you’re Penn Jillette, Michael Goudeau, Jason Garfield, or Vova and Olga Galchenko (the nastiest of the nasty), but it’s still a fun skill to possess. Teach yourself in your spare time, then break it out amongst friends; I guarantee they’ll be, at the very least, somewhat impressed.
And watch this Galchenko video for comedy gold...