The National Arboretum is looking for help with some outdoor projects, including cutting down invasive species and cleaning up the green house. I know this is the same day as Founders' day but you will get out in plenty of time to get all fancy and go! The travel time to the National Arboretum if you are traveling using the metro is about an hour and a half, so if you have a car please please sign up! Also, travel time is not included in the above time since it would be faster if cars are used rather than the metro. Wear something you don't mind getting dirty and comfortable shoes!