Studio 24: Open Sew In-Person
3-6 p.m. Thursday, April 24, NoBo Corner Library, 4600 Broadway, Boulder. Free
Have some old jeans to mend or want some company for your latest sewing project? Head to the NoBo Library, where you’ll have access to sewing machines and makerspace staff to answer any questions about your project — whatever it may be.
City Nature Challenge
4-6 p.m. Friday, April 25, Harney-Lastoka Open Space, 1400 N. Courtesy Road, Louisville. Free
Ready, set, bird watch! At this “bio-blitz” competition, you’ll be up against cities across the country in a race to find and document the most plants and animals through the iNaturalist app. Volunteer naturalists will lead a hike around Harney-Lastoka and Coal Creek Trail as you snap photos and try to rack up the most species. Registration required: bit.ly/BioBlitzBW
Stone Canyon Tree Planting
7:45 a.m. to noon and 12:45 to 5 p.m. Saturday, April 26 and Saturday, May 3, LEAF building, 304 2nd Ave., Lyons
The Stone Canyon Fire burned more than 1,500 acres in August 2024 — and now the landscape needs your help. Lend your time and a helping hand to this tree restoration project alongside community members of all ages. Bring shovels and wear gloves, eye protection, long sleeves and pants, closed-toe shoes and sunscreen. Water stations and restrooms are available onsite and shuttle transportation will be provided from LEAF to the planting site. Register: bit.ly/LyonsTreePlantingBW
Sew a Pet Stuffie
2-4 p.m. Saturday, April 26, inventHQ Makerspace, 6 Garden Center, Broomfield. Free
Want to immortalize a furry friend with your very own handmade stuffie? Head to Broomfield Library’s inventHQ Makerspace with a digital photo of your pet — images on your phone or a flash drive are great — and learn how to use a sewing machine with the guidance of an expert. No registration required.
Longmont Spring Market
Noon to 6 p.m. Saturday, April 26, Longmont Elk’s Lodge, 306 Coffman St. $5 or 2 cans of unexpired non-perishable food
Support your local businesses at the annual Spring Market in Longmont. Dedicate your afternoon to some quality retail therapy, and peruse art, jewelry, food and more from over 40 local vendors. And bring the whole family — there’s organized activities for little ones, and kids under 13 are free.
Earth Day, Every Day
10 a.m. to 2 p.m. Saturday, April 26, 105 W. Baseline Road, Lafayette. Free
Join this joint Earth Month celebration from the cities of Louisville and Lafayette and learn how to make a healthier planet. Hop on a blender-powering energy bike and make your own slushie, shop at a sustainable makers market, watch live wild animal demonstrations and see Jeff and Paige perform a science and nature-themed show for your kiddos.
Strider Bike Derby
3:30-5:30 p.m. Saturday, April 26, Calvary Bible Church, 615 Evans St., Erie. $28-$35 per entry; free to watch
Forget the Bolder Boulder: The cutest competitors are the tiny tots at the Strider Bike Derby. Participants age 2-5 scoot their balance bikes around curves, over obstacles and hopefully onto the pint-sized winners podium. Swag bags are given to all athletes. Formal dress and derby hats encouraged for spectators.
Sanitas Spring Gear Sale
Noon to 4 p.m. Saturday, April 26 and Sunday, April 27, Sanitas Brewing, 3550 Frontier Ave. Suite A, Boulder. Free
Already dreaming of shredding the slopes next winter? Maybe take a moment to enjoy spring while it’s here, you powder fiend. Lucky for you, you can grab a beer on the Sanitas patio, and rifle through last season’s discounted gear from Crystal Ski Shop, Stio, Zeal Optics and Angles Ski, Board and Fly Shop if you need a fix.
Boulder litter clean up
9:30 a.m. to 1 p.m., Saturday, April 26, PDQ, 5200 Manhattan Circle, Boulder. Free
Join the League of Women Voters (LWV) of Boulder County’s Climate Action Team as they partner with local zero-waste nonprofit Eco-Cycle to keep trash and microplastic out of our waterays. Grabbers and gloves will be provided, but bring extra if you can, along with a reusable water bottle.
Niwot Antique Auction
9 a.m. to 6 p.m. Sunday, April 27, Boulder County Fairgrounds, 9595 Nelson Road, Longmont.
Going once, going twice, sold! To the man in the funny hat. Head out to the BoCo fairgrounds and bid on what you don’t need, but absolutely cannot live without, from antique gas pumps to vintage oaken furniture — even an aluminum statue of everyone’s favorite grungy rodent Rat Fink.
International Tea
2-4 p.m. Sunday, April 27, Lafayette Library, 775 W. Baseline Road. Free
Celebrate Semana del Niño (Week of the Child), a yearly event dedicated to global child literacy, with sips and snacks from around the world. Learn about the food, beverages and culture of Argentina, England, Japan, Malaysia, Mexico, Palestine, Peru, Puerto Rico, Spain, Sudan and Thailand through local families. Uruguayan singer and guitarist Elisa Garcia will perform Latin American folk songs beginning at 2:30.
Drop-in Figure Drawing
6:30-8:30 p.m. Tuesday, April 29, NoBo Art Center, 4929 Broadway, Unit E, Boulder. $25
Swing by the NoBo Art Center in Boulder for this weekly session of facilitated, uninstructed figure drawing with a nude fine arts model. Bring your own drawing supplies. All skill levels and mediums are welcome. The center will provide workhorses, easels and clipboards to share on a first-come, first-served basis.