Drinking and Debating

-- Our old friends Drinking Liberally host a debate watching party tonight. Come armed with your best Keating Five jokes. Redline, 59 JFK St., Cambridge, 8 p.m. Free.

The Main Source

-- At age 17, Large Professor was already an accomplished producer, a founding member of underground hip hop powerhouse Main Source. He discovered—and produced hits for—Nas, taught DJ Premiere a thing or two about producing rap music, and cut tracks for everyone from Kool G Rap to Jeru the Damaja. He's celebrating the release of his new solo album, Main Source, his first non-instrumental LP since 2002. Underground Hip Hop Dot, 234 Huntington Ave., 6 p.m. Free.

Metal

-- Black metal does not come more correct than it does when it's coming from Uppsala, Sweden (home to Ingmar Berman and Carolus Linnaeus). Uppsala homeboys Watain bring "Satan's Hunger" to Cambridge tonight. With Withered, Book of Black Earth, Cold Northern Vengeance, and more. Middle East Downstairs, 472 Mass. Ave., Cambridge, 7 p.m. $15/$18.

Prog

-- Brooklyn duo USAISAMONSTER may have started as noise act, but they are thoroughly prog rock these days. Slow tempos, time changes, analog synthesizers, Dungeons and Dragons lyrics, the whole bit. The pair met while squatting; presumably they do not live in their mothers' basements. Great Scott, 1222 Comm. Ave., Allston, 9 p.m. $9.