The 30th anniversary of the first Secret Policeman’s Ball is as good a time as any for: 1) the festival’s braintrust to pat itself on the back; 2) the rest of us to enjoy the collateral benefits. Chief among those is archival footage of the concert series, which began in 1979 as a fundraiser for Amnesty International and combined a Monty Python–led comedy revue with unplugged performances by “surprise” guest rockers. The Secret Policeman Rocks incorporates footage from the 1979, 1981, 1987, and 1991 shows, including strong performances from Pete Townshend and Mark Knopfler and weak ones from Jeff Beck and Eric Clapton. The funny part? Despite its supergroup vibe, the whole thing smacks of an amateur’s enthusiasm, sidestepping the smugness of the various subsequent celeb benefits that it made possible.

THE FILM SHOWS AT 10 P.M. THE AFI SILVER THEATRE AND CULTURAL CENTER, 8633 COLESVILLE ROAD, SILVER SPRING. $6–$10. (301) 495-6720.