Roll up your pant leg—it's Bike to Work Day! Keep the good times rollin' this weekend with these three spring classics.  

Sandwiched between wave-ravaged bluffs, the beach at Tennessee Cove has long been a favored quick escape in the Marin Headlands. But its popularity shouldn't stop casual bikers from heading there for a good morning roll. Go early or late to avoid the noon-time crowds at the pocket beach. The mostly level 1.8 mile (one-way) Tennessee Valley Trail curves around lush green hills speckled in wildflowers; thanks to recent rains, the colors pack an extra punch. Near trail's end, purple bush lupine carpet the bluffs. Bring a snack and a book and kick back to watch the churning tides. Or park your bike and hike to higher ground by following the informal trails up the north bluff, where you'll get a nice vantage of the really high, and mighty, sea cliffs. Way to cove!

TIP: For a longer ride (approximately 10-12 miles one-way) that doesn't require a car, pedal from San Francisco across the Golden Gate Bridge, through Sausalito and along the Bay Trail to Tennessee Valley Road, then on to the cove. (On the multi-use Bay Trail in Mill Valley, look for the paved trail going left toward Tennessee Valley Road. It's 500 feet after going under Highway 101 and just before the small wooden bridge.)

Direction to Tennessee Valley and Cove: From San Francisco, go north on Hwy. 101 and take the Mill Valley/Stinson Beach exit. Follow Shoreline Hwy. until Tennessee Valley Rd.; make a left, and go 1.5 miles to the parking lot. No dogs.

For road bikers who want it all—flats, climbs, and hairpin downhills—the Peninsula's 22-mile Crystal Springs loop is old reliable. Starting from the well-manored village of Woodside, head north for 7.3 miles on the mostly flat and broad-shouldered Cañada Road, which parallels Crystal Springs Reservoir. (Enjoy Cañada's car-free "Bicycle Sundays" from 9:00 a.m. to 3:00 p.m. from Edgewood Road to Highway 92.) Put your quads to the test on the 6.3-mile climb from Highway 92 to the route's summit on Skyline Boulevard. The good news: All that climbing brings its rewards. On clear days, Half Moon Bay beams in the west, and to the east Palo Alto and the bay blend together in the background. Keep riding through a forest of sun-streaked redwoods; this mostly canopied section is a nice refresher on warm days. Then sit back and hang on for 8 miles of hairpin highlights on the quiet Kings Mountain Road; the only sounds will be your whoops of joy.

TIP: Grab a post-ride deli sandwich from Roberts Market in Woodside.

Ride this route early in the day; by mid-morning Hwy. 92 gets heavy with traffic heading to Half Moon Bay. Directions: Driving south on I-280, take the Woodside Rd./Hwy. 84 exit toward Woodside. In Woodside, park at the Museum/Town Hall parking lot off of Woodside Rd. Head north on Cañada Rd. for 7.2 miles. Turn left (west) on Hwy. 92 and go 2.7 miles. Turn left onto Hwy. 35 (Skyline Boulevard) going toward Big Basin; stay on this for 6.7 miles. Turn left onto Kings Mountain Rd.; descend 5 miles to Woodside Rd. Go 0.7 miles to your car.

Forget Slickrock. Dump Durango. Some of the best mountain biking we've found is just two hours from Market Street in a rugged patchwork of woods called Boggs Mountain, in southern Lake County. Packed with ponderosa pine and black fir, the forest is gloriously empty even on weekends. And the bikers who are there are apt to be old-school locals riding fully rigid mountain bikes and sporting neon Oakley Blades. They're ridin' for the pure love of it. And oh, those trails: toothpick-tight singletrack rolling up and down through the forest. You'll have your pick of the pack, so get a map at the kiosk located below the parking area near the fires station. (Our favorites were "John's" and "Karen's"—almost all the trails are on a first-name basis here—but we're pretty sure you'll find your own sweet sections.) The terrain never gets super-technical; it's just swooping singletrack that one local described "like low-level flying through a forest." Buckle up!

Directions to Boggs Mountain Demonstration Forest: Take Hwy. 101 North. In Santa Rosa, exit Hwy. 12 going east. Go about 4 miles. Turn left on Calistoga Rd. and take it about 7 miles until Petrified Forest Rd. Turn right and take it a few miles until you hit Hwy. 128, turn left and take it 1 mile. Turn right on Tubbs Lane, and then left on Hwy. 29. Take this all the way to Middletown. Once there, go north on Hwy. 175 toward Boggs Mountain. Just past Cobb, turn right where the sign says "CDF Fire Station" and park. Camping is available in the park. Dog-friendly!

SOLD OUT. Yep, San Francisco's renowned Nike Women's Marathon (and half marathon) is SOLD OUT again. But join Team In Training (TNT) and not only can you gain a spot in the sold-out race, you'll also support The Leukemia & Lymphoma Society's fight against blood cancers. TNT's got everything to get you started, including expert coaches to help you and your friends get fit for running or walking, and a like-minded community to share the sweat—and fun—along the way. BONUS: At the finish line receive an official finisher necklace designed by Tiffany & Co.

Running not your thing? TNT isn't just about marathons. On the new Moab Century Tour, you'll bike 100 miles through the gorgeous high desert and red rock canyons of Moab, up through the La Sal Mountains, and along the spectacular splendor of the Colorado River. Or, sign up for the Triathlon at Pacific Grove along the Monterey coast. Start with the "Kelp Crawl" swim, then ride and run the scenic course from Lovers Point.

If hiking's more your style, grab a spot on a hiking adventure in Colorado's Rocky Mountain National Park. Or stay in California and hike the famous Tahoe Rim Trail. No matter what activity you choose, you'll receive expert coaching—and you'll be supporting an important cause.

First step: Attend one of TNT's information meetings below. RSVP here!

San Francisco
Saturday, May 16, 9:30 a.m.: Presidio Sports Basement, 610 Old Mason Way
Thursday, May 21, 6:30 p.m.: Potrero Hill Sports Basement, 1590 Bryant St.
Wednesday, May 27, 6:30 p.m.: Presidio Sports Basement, 610 Old Mason Way

East Bay
Saturday, May 16, 2:30 p.m.: San Ramon Valley High School, 501 Danville Blvd., Danville
Tuesday, May 19, 12:00 p.m.: Veterans Memorial Building, 3780 Mt. Diablo Blvd., Lafayette
Tuesday, May 19, 6:30 p.m.: Pleasant Hill Community Center, 320 Civic Dr., Pleasant Hill

Peninsula & Silicon Valley
Saturday, May 16, 10:00 a.m.: Avenidas Senior Center, 450 Bryant St., Palo Alto
Monday, May 18, 6:30 p.m.: Embassy Suites Burlingame, 150 Anza Blvd., Burlingame
Wednesday, May 20, 6:30 p.m.: Sobrato Community Conference Center, 1400 Parkmoor Ave., San Jose
Thursday, May 21, 6:30 p.m.: Garden Court Hotel, 520 Cowper St., Palo Alto

North Bay
Thursday, May 21, 12:00 p.m.: Corte Madera Town Center, 100 Corte Madera Town Center, Corte Madera
Saturday, May 30, 9:00 a.m.: Petaluma Community Center, 320 North McDowell St., Petaluma

Monterey & Santa Cruz
Saturday, May 16, 10:00 a.m.: Embassy Suites Seaside, 1441 Canyon del Rey Blvd., Seaside
Tuesday, May 19, 6:30 p.m.: **Walk Information Only** Best Western Seacliff Inn, 7500 Old Dominion Ct., Aptos
Wednesday, May 20, 6:30 p.m.: University Inn & Conference Center, 611 Ocean St., Santa Cruz