The Boston Museum of Science is a Boston's biggest and best science museum, located along the Charles River.
The Museum of Science is home to a great variety of exhibits, as well as an Omnimax theater (which is IMAX with a curved screen) and a good planetarium, which also happens to have laser shows in the evenings. Cool exhibits include the world's largest Van de Graff generator, an interesting exhibit on the Big Dig, Virtual Volleyball, a computer center, an exhibit called "Mathematica" with spiffy ways to visualize concepts like probability and other topics in math, a live animal show, a musical staircase, and so much more. I believe the current tally for exhibits is upwards of 400.
The museum is fairly "kid-oriented," (lots of big buttons to press and colorful, shiny things) but that doesn't keep it from being enjoyable for older people also.
The coolest things there are the Mugar Omni Theater and the lightning show, which is run several times each day by a museum employee. He explains all about lightning, using examples like Tesla coils, a "kite and a key" demonstration, and why your car is a safe place during a lightning storm. At the end, he cranks up all the machines on stage to full blast and plays some dramatic music.
I have very fond childhood memories of the museum, as my family had a membership there and we must have gone there at least once a month. The greatest thing about it is that there's interesting stuff wall-to-wall from the second you walk in. They even have a computer made of Tinkertoys in the main lobby.
If you get the chance to go, make sure to go to the Omni theater and the lightning show. If you're eating there at the "Galaxy Cafe," make sure to try the spicy fries, which are pretty much the only good food there.
And thanks to mkb for reminding me about the audiokinetic sculpture, located in the lobby between the gift shop and the Omni theater/planetarium. which is a Rube Goldberg-esque machine in which pool balls are circulated around, producing all kinds of delightful whizzes, bangs and crashes.
Where it is:
The Museum of Science is across the Charles River between Cambridge and Boston.
They have a large parking garage with space for about 1,000 cars which isn't too unreasonably priced. The closest T stop is Science Park on the Green Line. From the station, there are signs leading to the museum, easily recognized by its large steeple and planetarium dome.
For more info:
http://www.mos.org or (617) 723-2500