Wind cooled the sweat on my face. Car lights blurred in my peripheral vision -- a stream of color coursing by. "Clear!" my race partner shouted, an intersection approaching, cars braking to our right.

It was 10 p.m., a Saturday in August, and I pedaled eastbound on Franklin Avenue in Minneapolis. My left hand gripped a map, our lone guide through the night.

It was the second hour of the All City Championship alley-cat race, an event that started behind a bike shop downtown. Alley-cat competitions, an obscure form of urban bike racing, demand athleticism along with street savvy and navigational skills.

"You've got to be fast, have a good head and know the city inside and out," said Jeff Frane, an organizer of the All City event.

A general theme in alley-cat races -- which are often low-key, underground events -- is to mimic the route a commercial bike messenger might take through the city over a single day. Competitors must find their way to a dozen or more addresses around an urban area.

In most races, competitors get a list of street addresses and landmarks. You create a route ad hoc and set off to ride to each point in any order, filling in clues and getting stamps at checkpoints before looping back to the finish.

A tough alley-cat can take hours to complete, with riders zooming through neighborhoods and industrial areas while reading a map. Bike in traffic. Look for clues.

Routes during the nighttime All City race, which has been held annually for four years, snaked more than 30 miles through Minneapolis and St. Paul.

"This race is designed to see who's the best in the city," Frane said.

Around the country, a few hundred alley-cat races are organized each year, according to Brad Quartuccio, editor of Urban Velo, a Pittsburgh-based magazine that covers city biking. He said alley-cat racing started as a "messenger-only thing," but now the number of messengers or couriers in each event is dwarfed by "commuters, bike nerds, racers, ex-couriers and people just looking for a good time."

Quartuccio added that Minneapolis is a national hot spot. The Stupor Bowl, a winter race in Minneapolis, attracts hundreds of riders and is in the running as the biggest alley-cat in the world.

At the All City race, there were about 150 competitors. Another Twin Cities event, Babes in Bikeland on Sept. 19, drew more than 160 entrants, making that women-only alley-cat the largest race of its type in the country, according to organizer Kayla Dotson.

I signed up for the All City not knowing what to expect. My bike, an urban-oriented ride with a fixed gear, fit in among the single-speed bikes stacked in the alley. We were behind One on One bike shop downtown.

Frane shouted, "Does everyone have a manifest?"

He was referring to the race clue sheet and guide, a printed page with almost 20 objectives for the race. Most were an address and a simple, fill-in-the-blank question. For example: "Linden Ave. Back of West 394 Sign. Year on back of sign?"

Racers could pick any route through the city to find the clues, making speed and strategy equally important to win.

Frane shouted "Go!" before my route was sketched on a page, but I jumped on my bike anyway. A mass of riders -- yelling, shoving, red safety lights blinking on their backs -- pushed out of the alley and into the streets.

On top of the manifest, race organizers printed, "I urge you to obey all traffic laws and ride responsibly. Your actions are your own." I thought of that cutting out into Washington Avenue, signaling a turn and tracking left.

At 1400 NE. Quincy St., the first stop on my route, I scribbled the clue answer. It was getting dark. I clipped in and pedaled north.

The 331 Club, a bar in Northeast, was stop No. 2. A race volunteer stamped my manifest and asked if I wanted a partner to race with: "She's from California, and she's lost."

The next three hours were a whirlwind race with Briana Forbes, 21, an ex-courier and strong urban cyclist from Los Angeles. We went from downtown to Northeast, to the Bryn Mawr neighborhood. Then south to Kenwood. Across town on Franklin Avenue. To St. Paul. To the University of Minnesota. To Bryant-Lake Bowl. To the Hexagon Bar at 2600 27th Av. S.

"Stamp here," a volunteer yelled.

Forbes wheezed while cranking up a hill. I strained to read a map in dim light. Cars roared past. Our legs spun, bodies moving ahead on the road, in a race, deeper into the night.

Stephen Regenold writes about the outdoors at www.gearjunkie.com.