“Folk rock” isn’t that good a description these days: Many acts seem to earn the tag just by owning acoustic guitars. What’s rare is a band that actually sounds like it was plucked from a cornhusking party in the middle of Appalachia, playing songs shot through with fiddle, banjo, and ukulele. But O’Death also adds a hard, nasty edge and vocals that would be more believable coming from a gnarled, crazy old man sitting on a falling-down porch with a shotgun in his lap (or maybe Tom Waits) than from some Brooklyn hipsters. Then again, maybe their street smarts mean they can bring some mountain life to the city without anyone daring to call them hicks. O’Death performs with Rock Plaza Central at 9 p.m. at the Black Cat, 1811 14th St. NW. $10. (202) 667-7960. —Kim Gooden

Constantin Costa-Gavras’ first film was a conventional crime thriller, The Sleeping Car Murder, but then all the director’s best-known works are crime thrillers—it’s just that the criminals are men who steal nations, extort democracy, and murder dissidents. This series features only three of the director’s films, but they’re among his best and made during a period (1967–1973) that was entirely congenial to their outlook. A Greek exile who moved to Paris at 18, Costa-Gavras transformed his chosen genre with his third feature, Z (at 7 p.m. Thursday, Sept. 6). It was the story of his own homeland, encapsulated in the actual case of a troublesome professor run down by a truck; the death may not be murder, but its investigation reveals that corruption has metastasized throughout the government. Released in 1969, when tear gas was in the air and anti-government feelings on the wind, the film expressed widespread distrust of Western regimes—but was set in Greece, so officials in other countries didn’t take it too personally. (In the United States, high school classes were taken on field trips to see it.) In 1973, Costa-Gavras struck closer to the American way with State of Siege (at 7 p.m. Friday, Sept. 7), which was also based on a real incident. “Terrorists” in Uruguay interrogate and kill an American diplomat, but as the story unfolds in flashbacks, the dead man no longer seems so innocent. Also included is 1967’s Shock Troops (at 7 p.m. Wednesday, Sept. 5), a taut tale of possible betrayal in the French Resistance. The films show at the Library of Congress’ Mary Pickford Theater, 101 Independence Ave. SE. Free. (202) 707-5677. —Mark Jenkins