Winter's rain brings green to the hills, water to the creeks, and a few fresh surprises. Discover the season's wonders on any of these three hikes.

There may be a bigger waterfall in Marin but there probably isn't a more intimate one. Twenty-foot Cascade Falls is tucked into a canyon behind the residential community of Fairfax. There's hardly any parking, few signs, and the short trail leading to the falls can be deceiving. All the more reason to seek out this elusive oasis. From the trailhead, walk alongside San Anselmo Creek. As you dip and wind through quiet Cascade Canyon you may be wondering—is there really a waterfall here? But within 20 minutes the creek picks up its pace as the faint sound of churning water echoes in the background. Soon enough you'll be at the base of the falls, where giant rock stair-steps lead to a wooden viewing platform. A few extra steps will get you to the edge. This little green grotto only comes to life during the rainy season, so get there soon. It's a good rush.

From westbound Sir Francis Drake Blvd. in Fairfax, turn left on Pacheco Ave., then immediately right on Broadway. Turn left at the next block onto Bolinas Rd. (aka Bolinas-Fairfax Rd.) Go a quarter of a mile; bear right onto Cascade Dr. Continue 1.5 miles until the end, where there's limited parking. Follow the High Water Trail to the right of San Anselmo Creek. At .5 mile, cross a wooden bridge and turn right at the T intersection. In a quarter of a mile you'll reach the falls. Dog-friendly!

This 5-miler has it all: interesting sandstone formations, wide blue views of the Pacific, and a glistening waterfall. Castle Rock State Park is a popular treasure of the Santa Cruz Mountains that stretches over three counties. Start by hiking through a fern canyon carved out by Kings Creek, admiring the honeycomb rock formations that are popular with climbers. Within a mile you'll reach Castle Rock Falls: a 50-foot gusher with a viewing platform that lets you lean out over the top of the falls. Keep going, and in a few minutes the tree canopy gives way to a surf and turf panorama; from 2,700 feet there's hardly a man-made structure in sight as the wild and rolling Santa Cruz Mountains surround you on all sides and the Pacific Ocean unfolds in the background. Return via the higher Ridge Trail with its equally impressive views (especially at Goat Rock). It's a royal experience.

For directions to Castle Rock State Park visit the Web site. From the parking lot take the Saratoga Gap Trail. Continue on this trail until it reaches Ridge Trail in 2.5 miles (there is a cutoff in 1.5 miles if you want to shorten the hike). Return on the Ridge Trail, passing Emily Smith Observation Point and Goat Rock. No dogs.

A sacred and secretive plot of land southeast of Mount Diablo has been intriguing people for thousands of years, yet you probably haven't heard of it. Vasco Caves Regional Preserve—named for eroded depressions in magnificent sandstone outcroppings—is co-managed by East Bay Regional Parks and the Contra Costa Water District. The number of people who visit is intentionally limited and reservations must be made. Expect a leisurely 2-mile group-led hike through blooming buttercups and barren blue oaks in a place that's spiritually and culturally significant. (Ten-thousand-year-old Indian rock paintings can be seen on a few sandstone boulders.) Vasco Caves also happens to lie smack in the middle of the densest population of nesting golden eagles in the world. Keep your eyes peeled for this massive raptor or others, like the red-tailed hawk and prairie falcon. Your friendly and knowledgeable guide will help you spot endangered red-legged frogs, tiger salamanders and fairy shrimp found in seasonal vernal pools. Vasco Caves is a little world of its own. Just don't tell anyone else about it.

Vasco Caves is open for guided tours from February to May and October to December. The tour costs $34 per person. For information and reservations call 888-EBPARKS. No dogs.

It turns out a whole bunch of people decided to do the seven-day bike ride from San Francisco to Los Angeles, to benefit the San Francisco AIDS Foundation. Still on the fence? It's not too late to join. Seven days on a bike sounds crazy, but everyone is excited about it. The AIDS/LifeCycle will be an amazing tour across California, seeing the state's most beautiful landscapes, from forests to the sea, not to mention relaxing country roads. (Haven't you always wanted to see what this state is really like without a car windshield in front of you?) Plus it's fully supported with gear transport, hot meals, pit stops, and even free massages (plan to get one of those every day!). It'll be a blast for a good cause: Check out this video to see what it's all about. Even better, join a training ride to learn more!

TIP: Weekend Sherpa subscribers get $20 off registration by using PROMO CODE: SHERPA. So whaddya say? Come ride with us!