Look out for that hookah-smoking caterpillar.

PARTY
Alice in Helixland
What: Costumes, tea party foods, and a silent auction to benefit Whitman-Walker Clinic.
Why: It’s a very important date.
When: Fri., 7-10 p.m.
Where: Helix Lounge, 1430 Rhode Island Ave. NW, b/t 14th & 15th Sts. (202-462-9001).

Moulin Rouge at Napoleon
What: Go wild at the Parisian spot with absinthe, sword swallowers, and spectacle courtesy of Alliance Francaise.
Why: Don’t be absent for absinthe.
When: Fri., 10 p.m.
Where: Napoleon Bistro & Lounge, 1847 Columbia Rd. NW, at Mintwood Pl. (202-299-9630). R.S.V.P. to 202-234-7911 ext. 31.

SHOP
Terra Fall Sale
What: Snag 20 percent off Robert Rodriguez and Catherine Malandrino.
Why: Put that wardrobe on Terra firma.
When: Thurs.-Sat., 11 a.m.-8 p.m.; Sun., noon-5 p.m.
Where: 1706 Connecticut Ave. NW, b/t R & S Sts. (202-232-8581).

SEE
Junior League Band with the Resurrectionists
What: Local bluegrass rockers get funky with a special Halloween costume show.
Why: Popped collar and pearls not required.
When: Fri., 9:30 p.m.
Where: Iota Club & Cafe, 2832 Wilson Blvd., Clarendon (703-522-8340).

Bollyblend
What: Costumed dancers pop, drop, and lock it to Indian beats.
Why: Don’t go for a jelly belly.
When: Sat., 3 & 8 p.m.
Where: Atlas Performing Arts Center, 1333 H St. NE, b/t 13th & 14th Sts. (202-339-7993).