DC trip

A little off topic.

I'll be vacationing in DC later this week (one of those rare vacations where we are not visiting family or volunteering) and I'm looking for good ideas for places to visit and places to eat.

The few places we know we want to see include:

• Smithsonian American Art Museum (I particularly want to visit the Renwick Gallery and the Lunder Conservation Center, of course)
• Textile Museum
• Library of Congress (I've scheduled a "behind the scenes" tour of the preservation directorate)

So, what are the places or exhibits that we shouldn't miss? (We are more 'art' people than 'history' people.) Is the Newseum worth the $20 admission? Any good restaurant suggestions? We'll be staying near the White House.

Thanks for any ideas.