The National Zoo's Halloween tradition Boo at the Zoo returns

• During the special after-hours access, guests can trick-or-treat between 30 stations and check out animal habitats decorated in spooky decor.
• The zoo's party animals are ready for fun, too, with special holiday treats. Humans will walk away with souvenir tote bags.

Details: You'll want to snag online tickets ASAP (starting at $35 for the general public). Parking passes ($30) are available as well.