The friends stand face-to-face, eyeing each other in mock anger. Taryn draws a hand back and aims a blow at Sydney's cheek.

There's a loud "whap!" Sydney recoils with an expression of shock.

It's all clowning, of course. As the girls demonstrate, Taryn stopped her hand inches shy of Sydney's face.

Sydney, the "victim," created the "whap!" sound by clapping her hands at the moment of "impact."

"It's about getting your timing right," Taryn says, sounding every inch the latter-day Charlie Chaplin. "If you get it right, no one will see the trick. Everyone laughs. Don't you think that's cool?"

The more, the merrier

In the course of his career, Rosman has clowned for two circuses (Clyde Beatty-Cole Brothers and Cirque Voila). He has juggled clubs, walked on rolling globes and strolled the tightrope on cruise ships, in Vegas and Europe, and on Leno and Letterman.

Locally, he does his annual "Squire on a Wire" routine at the Maryland Renaissance Festival, trots out his DumbWaiters act ("the world's most idiotic servers") for private parties and pedals his 9-foot-high unicycle at sites like the Inner Harbor.

One thing he has discovered over the years is that clowning's more fun in groups, which is why he formed his first teaching camp six years ago and now works with a team of teachers.

This week's group includes fellow clowning veteran Mark Lohr of Frederick; Lohr's daughters, Gena, 13, and Grace, 12; a stilt-walker named Cybele Pomeroy; and Rosman's own children, Sophia, 14, and Ethan, 12, both of whom are spry like their dad.

Rosman waxes rhapsodic about each artist, but above all, he seems a proud father. Few girls in the world can juggle or ride the rolo bolo (a plank on a cylinder) like Sophia, he says, and Ethan started juggling so young "he's doing things I'll never be able to do."

At one point Tuesday, the confident Ethan displays his latest trick: a spectacular juggling display involving five pin-shaped clubs.

He keeps them going for eight or nine seconds, a profusion of intricate motions, before missing one catch and letting them fall.

"I break a lot of fingernails" practicing that, Ethan says.

Michael Rosman is glad the campers have at least seen he's human.

"You're not that far away" from his level of skill, he cries.

No one garners more attention than Lohr, a burly man with a perpetual smile and a resounding laugh. Rosman proclaims him "the loudest clown in the world," and Lohr likes that idea.

When the time comes to split the group in two, he sprints to the far side of the gym, a gaggle of 7- and 8-year-olds screaming in his wake.

"Last one there's a rotten egg!" he roars, and the scene is bedlam.

Over there, they put some of Lohr's theories into effect. He calls himself a "Shakespearean clown" — one who acts out a character in situations — and he likes to cite the Rule of Three, a principle that says jokes, skits and stories work best when they come in three parts: a beginning, middle and end.