Celebrate Groundhog Day Lego Build-Along: 2 p.m. Sunday, Boulder Public Library, 1001 Arapahoe Ave., Boulder. With tens of thousands of LEGO pieces and the guidance of an experienced Play-Well instructor, participants will be able to build a groundhog. Power up engineering skills with Play-Well TEKnologies and tens of thousands of LEGO parts. Apply real-world concepts in physics, engineering and architecture through engineer-designed projects. Design and build as never before and explore crazy ideas. For ages 6-11, registration required for children attendees only. calendar.boulderlibrary.org.

Third annual Greatest .5k Ever: 9:30 a.m. Sunday, Sanitas Brewing Co, 3550 Frontier Ave., Boulder. It’s a .5k! Break the Dry January streak with a super fun run and beer at Sanitas Boulder. This will be a frosty fun run around the back lot of the brewery. Free, fb.me.

Boulder Friends of Jazz Jam Session: 1 p.m. Sunday, Avalon Ballroom, 6185 Arapahoe Road, Boulder. Come listen, play and dance to vintage jazz of the ’20s, ’30s and ’40s. $2-$12, 303-449-1888.

Film Social: 2 p.m. Sunday, Boulder Public Library, 1001 Arapahoe Ave., Boulder. Watch “Reading Rainbow,” the award-winning series hosted by LeVar Burton that sparks a love for reading. There will be snacks, a marathon and reading fun in the Canyon Theater. Closed captions provided. Rated TV-Y. calendar.boulderlibrary.org.

Littles Playgroup: 2 p.m. Monday, Boulder Public Library, 1001 Arapahoe Ave., Boulder. Form new friendships in this new playgroup for children ages 0-4 years old to have fun and caregivers to socialize. Sometimes it’s hard to connect with other caregivers and find playmates for the little ones, so here is an opportunity. Toys and light refreshments will be provided. Siblings welcome. All children must be accompanied with a caregiver. Registration required for each individual due to room capacity. calendar.boulderlibrary.org.

Aging Artfully — Bud Vase Pottery: 2 p.m. Monday, George Reynolds Branch, 3595 Table Mesa Drive, Boulder. For people ages 60 and older. Craft delicate, small vases designed to hold a single flower or a few stems. Guided by an experienced instructor, attendees explore techniques such as hand-building and personalize their creations with textures and shapes. Perfect for beginners and creatives alike, this class blends artistry and functionality, resulting in a beautiful, handmade piece to take home. calendar.boulderlibrary.org.

“Ghost Quartet” performance: 7:30 p.m. Monday, Dairy Arts Center, 2590 Walnut St., Boulder. “Ghost Quartet” interweaves four stories across seven centuries — a fairy tale about two sisters, an astronomer and a lazy evil bear; a retelling of Poe’s “The Fall of the House of Usher”; a purgatorial intermezzo about Scheherazade; and a contemporary fable about a subway murder. $25-$58, 720-468-0487, thedairy.org.

Floral Altar workshop with Yazz Atmore: 6 p.m. Tuesday, Dairy Arts Center, 2590 Walnut St., Boulder. Join the Dairy Arts Center and Yazz Atmore for a special floral altar workshop in honor of Black History Month. Check out the Black Futures in Art exhibition as participants come together to craft personal traveling altars. This workshop is an opportunity to play creatively and meaningfully with flowers and create an altar to connect with your ancestors and loved ones, past and present. Feel free to bring photos, trinkets, herbs or keepsakes to add an extra personal touch. This workshop is open to all ages. $25-$35, 303-444-7328, thedairy.org.