SOME ENCHANTED evenings, you will pay a lot of money to see superstars like Madonna, Paul McCartney and Luther Vandross.

And some evenings, you won't have to pay anything. Of course, some of the acts you'll be seeing you'll never have heard of. That's okay, though, because they've never heard of you, either.

That's how it is every summer in and around the capital. Major outdoor venues open their gates, concertgoers who opt for lawns pray against rain, and the most welcome fans are those that can be held in one's hand.

Outside of Fleetwood Mac (at Capital Centre July 18; tickets go on sale Saturday), there are no big reunion tours this summer (remember the Stones and Who at RFK last year?), but David Bowie, at Merriweather Post Pavilion July 18, is publicly touting his recently released CD catalog and insisting this is a farewell tour for many, maybe most, of his old songs.

The big-noise tours? Well, you just may have heard about Madonna, who brings her latest cross-marketing plan -- "Dick Tracy" film, "I'm Breathless" album, "Blond Ambition" tour -- to Capital Centre next Friday and Saturday. Tickets? Ha ha ha.

Paul McCartney, following on the heels of Ringo Starr's 1989 tour, is back on the road for the first time in 13 years, celebrating our independence from the British (and his from the Beatles) at RFK Stadium on July 4, and again July 6 (plenty of tickets available for the second show). Other RFK extravaganzas include the annual Budweiser Superfest on June 30 -- Luther Vandross headlines, with Stephanie Mills, Frankie Beverly and Maze and hot newcomers Toni Tony Tone; the Grateful Dead on July 12, celebrating a quarter-century of themselves (but without vendors this go-round); and the New Kids on the Block on July 17 (helpful hint: brings lots of extra cash for the ubiquitous T-shirts, caps, buttons, pinups, etc).

Summer '90 brings back a lot of acts that played here during the winter season and found Washington so hospitable they had to come here again: at Cap Centre, it's Billy Joel (July 13 and 15), Aerosmith (July 28) and Janet Jackson (Aug. 10, 11 and 13), while several acts move outdoors at the Post Pavilion this go-round, including Tears for Fears (June 15), Erasure (July 20), silly Milli Vanilli (July 22) and Sinead O'Connor (Aug. 26).

As for MIAs (that's a musician who's off the road for a year or more), Barry White lumbers in to DAR Constitution Hall (June 9), Suzanne Vega to the Kennedy Center (June 11), Tracy Chapman to the Post Pavilion (June 17), Bobby McFerrin to Wolf Trap (June 22), Jackson Browne to DAR (July 1). And it's CBGB's Revisited at the Post Pavilion on June 28, as the Tom Tom Club, Jerry Harrison of Talking Heads, the Ramones and Deborah Harry relive the late '70s. Also look for Public Enemy July 3, August/September dates from Phil Collins, Eric Clapton and Billy Idol, and an Aug. 8 debut from Britain's Soul II Soul, all at Capital Centre.

For environmentalists, Chip Davis and Mannheim Steamroller bring "Music of Nature -- a Concert for Yellowstone" to another national park, Wolf Trap (July 1 and 2) and Paul Winter settles in at the University of Maryland's Tawes Theatre (July 7). For the musically adventurous, Wolf Trap offers two classy quartets, the Modern Jazz and Kronos, performing separately and together (Aug. 6).

The Twist and Shout club may be gone, but the twisting and shouting will continue at the fourth annual Blue Bayou Music Festival at the Prince George's Equestrian Center in Upper Marlboro. This year's daylong event (July 14) will feature Carl Perkins, Little Milton, Lonnie Mack, Beausoleil and five other roots acts.

Despite Park Service budget cutbacks, Carter Barron Amphitheatre (the area's oldest outdoor venue) and Fort Dupont have busy agendas, and the two major folk (that's synonomous with free) festivals celebrate anniversaries: the Washington Folk Festival goes into its 14th year at Glen Echo Park this weekend, with the focus on the multiethnic cultural threads that enrich this region; and the Smithsonian's 24th Festival of American Folklife holds forth on the Mall (June 24-July 1, July 4-July 8). Your tax dollars will be at work focusing attention on the music, food, dance and crafts of the U.S. Virgin Islands and Senegal, and on "Musics of Struggle" (a world-overview suggesting how music and song can be used to express community identity and to mobilize people in their struggle for cultural, civil and political rights).

As these listings suggest, there's something for everyone and every taste; much of it is free and in sylvan settings (including the Sylvan Theatre, which hosts big bands on Wednesdays). Seek and enjoy.