Why hello, three-day weekend.

GROW
San Francisco Beard and Mustache Contest
What: Ogle some of the city’s best ’staches or enter your own (even if it’s fake) at this contest celebrating the art of facial hair.
Why: Proceeds benefit Smile Train.
When: Thurs., 6 p.m.
Where: Edinburgh Castle Pub, 950 Geary St., b/t Polk & Larkin Sts. (415-885-4074). Admission is $5.

TASTE
Citizen Cake Pop-Up at Orson
What: Sample some of Elizabeth Falkner’s cookies, cakes, and sweets before they debut at the highly anticipated Citizen Cake on Fillmore.
Why: Have your desserts first.
When: Fri. & Sat., 11 a.m.
Where: 508 4th St., b/t Brannan & Bryant Sts. (415-777-1508).

SHOP
Spring Clearance Sale at BellJar
What: Save 30-65 percent on gorgeous frocks at one of our fave Mission boutiques.
Why: Have a side of BBQ with your shopping on Saturday.
When: Fri. & Sat., noon-7 p.m.; Sun., noon-6 p.m.
Where: 3187 16th St., b/t Valencia & Guerrero Sts. (415-626-1749).

SEE
Rush Opening Reception
What: Iconic filmmaker John Waters’s latest solo exhibit, named for a type of liquid incense that’s popular among club-goers.
Why: Works include a giant sculpture, photos from his flick Pecker, and film-still collages.
When: Party, Thurs., 5:30 p.m. Exhibit thru July 9.
Where: Rena Bransten Gallery, 77 Geary St., at Grant Ave. (415-982-3292).

SIP
Fashionista Happy Hour at The Rotunda at Neiman Marcus
What: A new menu of delectable bites (pulled pork sliders, truffled popcorn) served under the dome, along with discounted drinks like $7 bubbly.
Why: A postshopping treat.
When: Thurs., 4-7 p.m.
Where: 150 Stockton St., at Geary St. (415-249-2720).

GIDDYAP
Band of Horses at Amoeba Music
What: Snag a copy of their latest album, Infinite Arms, on CD or vinyl and get a signed poster and priority admission for the sure-to-be-packed in-store show.
Why: Free rockin’ and rollin’ in the Haight.
When: Sat., noon.
Where: 1855 Haight St., b/t Stanyan & Shrader Sts. (415-831-1200). Limited to the first 300 peeps.

Photo: Powerhouse Museum Collection / Flickr