Wooly Mammoth Theatre Company, located at 641 D Street, NW, is scheduled to celebrate the 2017-2018 theatre season through a free community-friendly party on Sept. 16 from noon to 4 p.m. More than 20 of Washington’s theatre companies will be present to share upcoming productions. Food and refreshments will be served. There will also be live performances and giveaways. For more information, visit downtowndc.org.