"Messages to Washington," running through Oct. 12 at the Washington Project for the Arts, is an eclectic show of American detritus -- letters, pictures, objects -- that constitutes the response to a call for personal messages directed at the government (in almost any form). The show was organized by Group Material, a New York artists' collective. The exhibit seems somewhat thin, and the appeal is more verbal than visual. CLASSICAL MUSIC The Phillips Collection opens its season today with the Carnegie Trio playing selections from the piano trio repertoire. Also today, the Washington chapter of Artists to End Hunger will present a benefit concert at the Rockville campus of Montgomery College. Featured artists will include soprano Phyllis Bryn-Julson and violinist Jody Gatwood.

The International Conservatory of Music will feature music from many parts of the world in a faculty recital tomorrow night at the Strathmore Hall Arts Center on Rockville Pike.

Those who want a preview of Tchaikovsky's "Eugene Onegin" before the Washington Opera's production can see a performance by the Chicago Lyric Opera, Wednesday night on Channel 26. DANCE A broad sampling of Washington-based dance troupes and artists will give free performances on the Adams-Morgan Day Dance Stage today from noon until 7:30 p.m. as part of the annual neighborhood festival. This year, the dance groups will have a large stage available on a National Park Service Showmobile, to be located on Columbia Road near the intersection with Champlain Street NW. Such groups as the Spanish Dance Society, Perlo/Bloom & Company, the Tap Quartet, the Sahara Dancers, African Heritage Dancers and Drummers, and the D.C. Contemporary Dance Theater will be among the 17 attractions. The distinguished Japanese American dancer-choreographers, Eiko and Koma, based in New York, will make their Washington debut at the Dance Place this weekend in programs Friday and Saturday nights. POP MUSIC Samplings of Washington music are available free today in both Takoma Park and Adams-Morgan. In Takoma Park, the Ninth Annual Folk Festival is headlined by sympatico soul Pete Seeger, who grew up nearby, but most of the bands live in the communities they'll be entertaining today.

Two excellent blues-oriented acoustic guitarists come to town: Geoff Bartley appears at the Takoma Cafe on Monday, while John Mooney, who recently recorded a duet album with the Nighthawks' Jim Thackery, is at Friendship Station on Thursday.

Back in the late '60s and early '70s, they were one of black pop's hottest bands (the only thing hotter was their album covers); now the Ohio Players record as Sugarfoot, but their Friday and Saturday shows at the Ibex will feature all the old hits as well as some hope-to-bes.

Master drummer Ola Tunji, who first popularized authentic African music in America, celebrates three decades of music with several other African bands and special guest Della Flack at Howard's Cramton Auditorium on Friday.