Shephard Fairey and Al Burrows will be at the Corcoran on Friday for a discussion about their work and how political issues inspire their pieces. Shepard Fairey’s Big Brother City courtesy of Irvine Contemporary. DCist’s guide to lectures and discussions in the D.C. area. Monday: >> Tonight from 6:30 to 8:30 p.m., head over to the Greenbelt Library at 11 Crescent Rd. for a free vegan dinner and lecture by Michael Greger, M.D., the…