A man takes his dry cleaning from a parked car and heads indoors; a woman inhales the last drag from a cigarette and flicks it off her back porch; someone else deposits his trash into the dumpster, while overhead a 727 makes a noisy approach to National.

An alley you say?

Right. But not just any alley (the Porta Potti is a dead giveaway). This is Theatre Alley, where the show competes with the urban environment for the audience's attention.

Source Theatre's inaugural production in Washington's only outdoor theater is Tom Eyen's campy comedy "Women Behind Bars," which runs through Saturday.

On stage, half-clad women, bandying about marital aids, scream obscenities and make lesbian overtures. In the cheap seats -- the roof of an adjacent building -- six shirtless neighborhood boys beat the actresses to their lewd lines a la "Rocky Horror Picture Show," reciting them with antici . . . PATION.

Theatre Alley. And the Meese Commission is nowhere to be found. Shakespeare, Rolling Along

Continuing with the theme of nontraditional theater spaces, comes now Shakespeare on Wheels -- a 40-foot flatbed trailer atop which "Romeo and Juliet" rolls into town Monday at 7 p.m. outside of National Place. The roving replica of an Elizabethan stage is the brainchild of William Brown, chairman of the theater department of the University of Maryland/Baltimore County, who introduced the concept while teaching drama in 1964 in Africa. Shakespeare on Wheels will be making 14 stops in the Baltimore-Washington area during the summer; for further information call (301) 455-2065. Mammoth Extension

It's Lucky 13 for the Woolly Mammoth Theatre Company, which announced last week it has extended its three-play repertory series through Aug. 30 after 13 weeks of sold-out performances. This season -- Harry Kondoleon's "Christmas on Mars," T.J. Edwards' "New York Mets" and Terrence McNally's "And Things That Go Bump in the Night" -- has been the most financially successful in the theater's six-year existence, according to managing director Linda Reinisch.

Reinisch credited the strong showing at the box office to positive reviews for all three productions as well as word-of-mouth advertising among Washington theatergoers. Citing a recent survey of more than 600 single-ticket buyers, she reported that when asked what made them decide to attend Woolly Mammoth, their top three responses (in a multiple response survey) were: friends (44 percent), quality of performance/reputation (38 percent) and play selection (26 percent). 'Saints' and Actors Equity

When "The Saints of Mercy Mission" opens Thursday at the Castle Arts Center in Hyattsville, it will mark one of the few times that Actors Equity, the union for professional performers, has granted a guest artist contract, ordinarily reserved for shows not competing with Equity houses (such as university presentations), to an all-artist production, with the playwright, actors, designers, director and stage manager doubling as producers of the play. The significance? Should the concept prove successful it will mean more work for Equity members, but more importantly, it could mean Equity-caliber productions at reduced ticket prices. ANT's Triple Feature

Richard Thomas and David Warrilow, who were last seen in Washington in the American National Theater's "The Count of Monte Cristo," will be reunited in "Two Figures in a Dense Violet Light" Aug. 9-23 at the Kennedy Center's Free Theater. ANT director Peter Sellars will direct the evening of three one-acts -- Samuel Beckett's "Ohio Impromptu," Ezra Pound's translation of "Tsunemasa" and Wallace Stevens' poem "Angel Surrounded by Paysans." Theatergoers will be admitted on a first-come, first-seated basis, with priority given to ANT members. Festival Showings

Landon Coleman's "The Pride of Burnside Heights," the Eugene O'Neill Center's 1986 New Play Contest runner-up, is among this week's offerings at the ongoing Washington Theatre Festival at Source Theatre. The one-act play, which opens Friday in the Warehouse Rep, painfully recounts a night in the lives of two male prostitutes. The play will be presented with Washington playwright Mark Scharf's "Blood Secret." For complete festival information call 462-1073.