The ultimate nerd sport, at least if you define "sport" as something that requires physical activity. Otherwise, D&D is the ultimate nerd sport.

This image looks amazing, until you realize he's wearing a kilt.

Just The Facts

  1. Juggling is the practice of object manipulation. Depending on who you want to get in a flamewar with, this means that balancing something on your chin, kicking a barrel around with your feet, and throwing three balls in the air in a pattern are all juggling.
  2. Juggling is thousands of years old, with historical records stretching back to ancient Greece .
  3. The vast majority of jugglers are not, in fact, clowns (in the literal sense, anyway), but rather nerds. This makes attempts to make juggling �street� or otherwise badass absolutely fucking hilarious, since the last time juggling was seen as remotely edgy or badass was
  4. There are jugglers out there who have honed themselves to an incredible level of reflexes and skill. Their reward for the thousands of hours they�ve dedicated to this ancient sport and art is low-paying jobs as acts in Vegas, clowns in circuses, and as entertainment/being a waiter on

What Is Juggling?

That's a complicated, loaded question among jugglers, and literally nobody else. The best answer is "Juggling is a hobby done almost exclusively by huge nerds."

Juggling takes practice. Lots and lots of practice, which means a huge time commitment, which is why the vast majority of people can't juggle three balls, because they have better things to do like get laid and talk to friends. Only people who either have no life or date a juggler and thus have no life ever learn to juggle.
Jugglers tend to fall in three camps: numbers jugglers, who are people who try to learn to juggle as high a number of objects as possible; technique jugglers, who'd rather learn lots of juggling tricks, and life-skills-free jugglers, who do things like joggling (yes, jogging while juggling), juggling while driving, and generally striving as hard as humanly possible to make the hobby/sport look even dorkier and more ridiculous than it already is.

Juggling as a Sport

There's a movement, driven almost entirely by a guy named Jason Garfield, to make juggling a sport on par with chess and the three-legged race for least-interesting televised event. Garfield is a fairly unique professional juggler in that instead of being a professional entertainer or enormous dweeb, he's a loud, obnoxious, trend-hopping douchebag jock straight out of an '80s comedy who gets in everybody's face and tries to pick fights with anybody who dares question his view of juggling as, like, the ultimate test of mind and body.
While it's true that Alfred Pujols probably can't sustain a seven-ball cascade, Garfield apparently doesn't realize that hitting a home run is vastly more impressive to the majority of Americans, and that, say, martial artists breaking a concrete block with their bare hands is vastly more impressive to the human race. Either of the two would probably be more useful in a bar fight than Jason Garfield.
It's true that juggling requires strength, stamina, and incredible reflexes. It should be noted, however, that the same is true of curling.

Basic Juggling Patterns

The Shower:
This is a bunch of balls going around in a circle.
The Cascade:

This is the most basic pattern of juggling. It's a figure eight.
Two in One Hand:

Two balls going in a circle, in different directions.