They've stopped the White House tours. Look on the bright side, at least you don't have to get up at five to get tickets.
I haven't been to the Spy Museum, but I've heard that it's cool.
The sculpture garden just east of the Natural History Museum is worth a walk-through.
The Insect Zoo upstairs in the Natural History Museum is pretty cool, unless very big hairy spiders are a problem.
Check out the schedule for the I-Max theater at the Natural History Museum.
Restaurant recommendations:
Old Ebbitt Grill (15th St between F & G), one block from the White House. Classic DC lunch spot. It has everything from burgers on up and it's very reasonable. Reservations are just about required, especially at lunch.
The rooftop restaurant at the Hotel Washington (15th and Penn). It has the best view in the city. The food's okay and not expensive (sandwiches, etc.).
Kinkaid's (20th & Penn), another DC favorite. Seafood is what they do best. Kind of expensive, but a very good bet.
For something a little more exotic, try Yanyu for great Asian food. It's on Connecticut Ave. in the Cleveland Park neighborhood, just a half block down from the Cleveland Park Metro station. Expensive, but very special.