Everyone is part of the in crowd but me. Okay, I'm dumb - what is a MS-13.
No problem. MS-13 is a street gang that has a large base in Northern Virginia and have been responsible for some recent viscious attacks using machetes (weapon of choice for them). MS stands for "Mara Salvatrucha". The gang has roots in El Salvador and sprang up in California then somehow became big in NoVA. Hope this helps!