On a budget, weigh it — The Phillips Collection isn't cheap for what it is.
~$20 adult (weekends)
A welcome antidote to the giant free museums — small, intimate rooms where you can stand alone with Renoir's 'Luncheon of the Boating Party'. The honest catch: it's ticketed (unlike the Smithsonians), and its compact size means it's a focused hour, not a half-day.