Memorial Day weekend marks the unofficial start of summer, and spots around DC are celebrating with outdoor activities, rooftop barbecues, boozy slushies, and brunches for your day off. Weekend Fun Hi-Lawn, an outdoor picnic spot and bar on the top of Union Market. Photograph courtesy Hi-Lawn. Anxo 711 Kennedy St., NW The Brightwood Park cidery Welcome the unofficial summer with these fun Memorial Day food events in DC.