Look on eventbrite for things to do and get on mailing lists. There's so much that I can never go to all the things I want

Check all the Smithsonian's for events, library of Congress every Thursday night, dance classes, salsa nights on Tuesday in Arlington. Get a hobby like learning about art, wine tasting (sommelier class?), cooking new foods, growing garden, join community garden, exercise classes, write a book. We are jealous of your free time -- take advantage! Also read '4 Hour Work Week' for help learning what you really want to do.