Pipilotti Rist's 'Pepperminta,' at the Hirshhorn, is a costume for a bold After Hours partier on Friday.

Hirshhorn After Hours has prohibited costumes for the sake of protecting the museum's art — and also to keep the event from turning into just another Halloween party. So leave your Sexy Hirshhorn Bubble costume (lingerie, balloon) at home. You can still dress up, though — provided your costume doesn't actually look like a costume. Try going as one of these art world figures that are more mildly attired.

Bob Ross: Blue shirt, untamed 'fro, slightly graying beard. Done and done.

Cindy Sherman: Oh come on, this could be anything. Here are some examples.

Lenny Campello: Deemed one of the art world's top mustaches by TBD's The List, a Lenny Campello costume would not arise suspicions from any guards. Just start growing a lustrous mustache.

Jerry Saltz and Roberta Smith: Couples costume! Work of Art judge and New York Magazine critic Jerry Saltz is easy. Just wear a dark suit, no tie, and obsessively check your Facebook account from your smartphone. A Roberta Smith (Saltz's wife and New York Times critic) costume requires a chestnut bob, thick-rimmed glasses, and a smirk.

Piet Mondrian: This store-bought costume, with tights, flats and a reasonable hairstyle, could almost look like a normal dress. Almost.

Pepperminta, by Pipilotti Rist: Bonus points for topicality, and effort: Pepperminta is currently showing at the Hirshhorn (so how could they possibly reject it?), and assembling a costume in this many garish colors will require some work. Worth it!

Philippa Hughes: Just ask Arlington Art Center's Jeffry Cudlin to borrow the costume he already made.

Gordon Bunshaft: Hirshhorn designer, pipe smoker, bow-tie wearer.

Marina Abramovic: Just wear a Snuggie.