Once I saw a bear riding my bike.

I know, that's an old joke, the kind of gag Groucho Marx would've thought up if he'd ever competed in the Tour de France. "How the bear got on my bike, I'll never know." For me, though, the bear was no laughing matter.

It was a sunny July day. Inspired by Lance Armstrong's uphill battles in the Pyrenees, I searched for a steep, challenging hill. I finally found one in a sleepy town in New Hampshire. It was my own personal Alpe d'Huez.

"This is impossible," I told myself, gazing up. It was crazy to think anyone could ride a bicycle up that wall. Heck, if the road were any steeper, I'd need ropes and pitons instead of pedals.

The hilltop protruded into a low cloud. I shifted down and started the ascent.

"You must have the strongest legs in the world, buddy!" a man on the sidewalk shouted.

"I'm working on it!" I called back.

A paved road lined with houses led toward the top. Halfway up, a boy about seven years old saw me, blinked in astonishment, and hollered to a friend somewhere behind his house: "Biker! Someone's riding up the hill!"

"No way!"

The first kid shouted again, impatiently, "Look! Look!"

Apparently no one had ever ridden a bicycle up that particular hill before. I was the afternoon's entertainment.

Huff, puff. My legs burned; my lungs ached. Lance Armstrong and his legacy, I decided, had nothing to fear. My increasingly slow pace wasn't going to win any endorsements at the Tour de France. I gritted my teeth and kept going anyway.

Soon the houses stopped and the trees closed in. I was almost to the summit. That's when I encountered the 400-pound mama bear and cub.

Usually on my rides across rural New England I encounter fox, deer or moose. Harmless creatures. Dogs sometimes chased me. But I'd never been chased before by hungry black bears.

The bears loped out of the woods and were halfway across the road when the mama bear must have heard me. She stopped and did a double take. We were only about twenty feet apart.

Fortunately, I scared the bears more than they scared me. I was breathing hard, with a terrible grimace of pain on my face. The adult bear must have thought, "Holy twigs and blueberries, that guy looks mean!" because she fled into a grove of apple trees on the far side of the road. The little cub scurried after her.

I continued to the top and turned around only to meet four more bears on the way back down. Mama bear must have summoned reinforcements.

This time the bears ambled across the road, in no hurry to get out of the way. I decided to slow down and let them cross at their leisure rather than charging at them at 40 mph. They appreciated my gesture and decided not to eat me.

My adventures weren't over yet. Back on the flats, I crossed paths with a creature even scarier than bears. I'm still not sure what it was. Perhaps just a hawk or an eagle, but I'll never know for sure. All I ever saw was the creature's shadow. It had wings-big wings. The shadow of the flying monster darkened the sky.

Glancing back over my shoulder into the sun, I blinked, shut my eyes, and turned my head away. Whatever was up there was flying low, directly between me and the sun. Gazing down, I could see the silhouette of wings, enormous wings, seeming to sprout from my own shadow's back. Whatever the animal was, it flew right overhead.

For one frightful instant I feared I was going to be eaten by a pterodactyl. I imagined the creature clasping me in its talons, bicycle and all, and carting me off to some mountain aerie for dinner.

I didn't want to be on the menu. I peddled faster. Geez, I thought, first bears, now ancient, predatory reptiles. What's next? All I wanted was to get home, where it was safe.

Watch out Lance Armstrong. Turns out I'm a world class athlete when being chased by bears and toothy, flying reptiles. I finished my ride in record time.