What better way to honor those who have fallen this Memorial Day weekend than to support their children? Run in the "450 for the Fallen" relay to help the Children of Fallen Patriots Foundation provide scholarships and educational counseling to kids who have lost a parent in the line of duty. Massachusetts legs of the relay are Friday and Saturday, May 23 and 24; details at www.450forthefallen.org.

Celebrate another great organization and the volunteers who make a huge difference in kids' lives at the Big Brothers Big Sisters of Massachusetts Bay's "Big of the Year Gala," where former Mayor Thomas Menino will receive the sixth annual Excellence in Mentoring award. Thursday, May 22, Sheraton Boston Hotel; more info at http://www.bbbsmb.org/site/c.9gKMJZMxF7LUG/b.8514495/k.53B2/Big_of_the_Year_Award.htm. 

Not equipped for summer yet? Head on down to Athleta's Summer Prep Party Thursday, May 22, from 7 to 9 p.m. to check out what's new and stock up. Other vendors will be there, too, including Yasso Frozen Yogurt, Boston Body, Benefit Cosmetics and more. 92 Newbury St. in Boston, 617-587-9830. 

It's a hip, acrobatic circus. It's a speakeasy. It's…you dressed to the nines and ready to dance the night away at the "Speakeasy Circus" at OBERON! With an underground cabaret that takes place on and offstage, shady bootleggers and deal-making gangsters, you'll have to make sure you save some sass for the dance party that goes until 1 a.m. Friday, May 23, 7 and 10 pm, 2 Arrow St., Cambridge, info and tickets at http://americanrepertorytheater.org/events/show/speakeasy-circus.

Want a night that's "Out of This World?" Spend an evening with the Boston Pops! Hosted by Leonard Nimoy, the Pops will perform an array of music inspired by outer space, including Holst's The Planets (with a film including NASA visuals), the theme from Star Trek, music from 2001: A Space Odyssey and a selection of John Williams's scores from Star Wars, E.T. and Close Encounters of the Third Kind. Friday and Saturday, May 23 and 24, 8 p.m., at Symphony Hall. Tickets $24-$94; call 888-266-1200 or go to http://www.bso.org/Performance/Detail/60556.

Memorial Day weekend marks the unofficial beginning of summer. Set the standard for a relaxed and refined season by greeting it with a sunset sail around Boston Harbor. Two-hour tours on the Adirondack III depart nightly at 6:30 starting on Friday. Tickets are $52; you can buy a drink (non-alcoholic are complimentary) and bring your own picnic dinner! More information and tickets at http://www.boston-sailing.com/Schooner-Adirondack-III.