Harvard Book Store Summer Warehouse Sale 2014 from 10 a.m. to 6 p.m. Saturday and Sunday at the store’s warehouse, 14 Park St., Somerville. Free.

This biannual sale lets book lovers run rampant (as rampant as book lovers do) through Harvard Book Store’s 6,500-square-foot Somerville warehouse to search among some 25,000 low-cost used, rare and remainder books. This time the store awarded early entry via five golden tickets, “Charlie and the Chocolate Factory”-style, to people sending in a haiku about book browsing and book discovery. Its other innovation in warehouse sales lets anyone compete: Staff will be searching Twitter for a buyer’s tweet using the #HBSWarehouseSale hashtag to highlight a favorite find. One winner each day will get a $25 Harvard Book Store gift card. (The store is on Twitter at @HarvardBooks.) Information is here.

Boston Games Forum: June Playtest Party from 2 to 6 p.m. Saturday at Microsoft’s New England Research & Development Center, 1 Memorial Drive No. 1,  Kendall Square. Free, but you have to RSVP; it gets you into the event and after-party.

More than 40 independent game developers get to show off their newest work to the Boston Games Forum crowd and visitors, demoing games and getting feedback. That means games fans get to try more than 40 games for a glimpse at the future of their parties and game nights. Information is here.

The Experience: The Acoustic Alliance from 7 to 10 p.m. Saturday at Lilypad, 353 Cambridge St., Inman Square. Tickets are $10.

Performers Alowishes Amore, Jamie Simons, Lydia Lyon and Ed Louis combine for an evening of painting to improvised music in what’s described as a “first-ever night of soul, singing, wine, conversation and popcorn.” The art showcases grouped together as The Experience have a new-agey feel, with organizers saying they are “meant to motivate, engage and provoke positivity and creativity between people. All involved in the show, including the audience, will have a memorable and inspiring experience. The goal for the team behind The Experience is to promote good vibrations and to captivate their audiences. All inclusive, thought provoking music and artistic pieces are what these shows are all about.” If that’s your vibe, information is here.

Calamity #6 variety show at 8 p.m. Saturday at The Democracy Center, 45 Mount Auburn St., Harvard Square. Entry is $10, or $6 if you bring a snack.

Calamity Co. Dance brings Calamity #6, a modern and pop art variety show with dance, music, comedy, theater and visual art to Harvard Square with promises of “a night of silliness, friendship, snacks and engaging, collaborative art.” Visitors are invited to come get to know the artists and their work in a casual environment, then join in a dance party “that will inevitably end the evening.” Artists include Nicole Beauchaine, comedian Wes Hazard, contortionist Dorothy Louisos, musician Sam Mulligan, Anna Reyes and the ladies of Calamity, including Molly Hess, Amy Mastrangelo and Meghan Riling. Information is here.

Cambridge Symphony’s Pops on the Lawn 2014 at 3 p.m. Sunday at Sennott Park, Broadway at Norfolk Street, near Central Square. Free.

The nonprofit community symphony has prepared a variety of pops favorites, including patriotic songs, Broadway tunes (from “Wicked,” “Chicago,” “Oklahoma” and “Grease”) and family-friendly classical favorites for this annual event supported by a Volunteer Ventures award from the MetLife Foundation. Bring a blanket or lawn chairs to put on the grass, but keep an eye on the weather and the symphony website for rain updates; the rain location is the Area IV Youth Center at 243 Harvard St., next to the park.