Ride Around Clark County, 6:30 a.m. open; course closes by 5 p.m. The annual cycling event features 18-, 34-, 66-, and 99-mile rides. Each route loops back to the starting point at Clark College, and includes aid and rest stops. Helmets are required. Hanna Hall, Clark College, 1820 Fort Vancouver Way, Vancouver; $25 to $40; $15 for ages 13 to 17 with a paid adult; free for ages 12 and younger with a paid adult. www.vbc-usa.com/racc
USGS Volcano Open House, 10 a.m. to 5 p.m. Mount St. Helens officials will offer information about monitoring technologies, and volcano research and science for the 35th anniversary of the volcano’s eruption. There will be hands-on activities, demonstrations, and visitors can bring in a rock for geologist identification. USGS-Cascades Volcano Observatory, 1300 S.E. Cardinal Court, Building 10, Suite 100; free. 360-993-8973 or http://volcanoes.usgs.gov/observatories/cvo
24th annual Walk Run for the Animals, 7:30 a.m. registration, 9 a.m. start, 12:30 p.m. awards. Animal lovers and their pets can take part in a dog-friendly walk or timed run to benefit the Humane Society for Southwest Washington. After the race, there will be a Party in the Park, where animal-related businesses will offer information about their products and services. Participating dogs must be kept on leashes. Esther Short Park, Columbia and West Eighth streets, Vancouver; $35, free for ages 12 and younger. www.southwesthumane.org/walk-run
Fairs & festivals
31st annual Cinco de Mayo Fiesta, 11 a.m. to 11 p.m. May 2, 3 and 5. This celebration of Latino culture and traditions features live music, authentic food, traditional dance, lucha libre wrestling, a carnival, an artisan village and a children’s area. Waterfront Park, 1020 N.W. Naito Parkway, Portland; $8, $4 for seniors and ages 6 to 12; free for ages 5 and younger. www.cincodemayo.org