I know I can be a curmudgeon, but most of the museums that were cool when I was a kid now suck, and suck bigtime. They have become giant malls; massive amounts of public museum space are filled with [unfree] IMAXes, pernicious gift shops and corporate hype. The FDR Memorial, which wasn't there last time I really did DC, had free parking and some of the best anti-war slogans around.