After the daytime visitors have left, many museums reopen their doors for the second shift of explorers: adventurous souls willing to spend the night among such unusual bedfellows as mummies, a giant squid and snoring strangers. Here is a sampling of sleepovers at natural history and science museums.

The American Museum of Natural History in New York brings "A Night at the Museum" to life, with animal encounters (bats, wolves, birds of prey), a 3-D film of the oceanic world, a fossil hunt and more ($145 per person; 1-212-769-5250;

The Carnegie Science Center in Pittsburgh geeks out with theme nights, such as Engineer the Future, Robotics and Sci-Fi ($39; 1-412-237-1637;

At the Cincinnati Museum Center, choose your fancy for the evening: superheros, Legos, dinos, wildlife and, for super-sleeper-achievers, STEM — science, technology, engineering and mathematics ($30, or $45 for Lego night; 1-513-287-7001; cincy overnights).

Chicago's Field Museum, home of Sue, the world's largest T. Rex, offers Dozin' With the Dinos. The event includes a movie about the T. Rexette, a flashlight tour of ancient Egypt and a meet-and-greet with backyard bugs ($65; 1-312-665-7525; field programs/dozin-dinos).

The Natural History Museum of Los Angeles County throws specialty sleepovers such as Camp Dinosaur, Camp Mummies and Camp Butterfly ($75; 1-213-763-3499;

Andrea Sachs