"We hope you enjoy yourself, " says a sign outside "The 7th Dollhouse Invitational" show at Middendorf/Lane, 2009 Columbia Rd. NW. It would be hard not to.

The show has nothing to do with dolls' abodes, but much to do with small-scale art with a sense of humor. It was conceived in 1974 by a group of graduate students at the University of Illinois "asan alternative to juried shows and commercial galleries." There is more than a modicum of irony in the fact that their show ends up in a commercial gallery. Although the works are not for sale, a list of artists' addreses hovers nearby, just in case.

Idealism aside, the show is a welcome chuckle in a summer of high seriousness, and the 38 invited artists (we are not told by whom they were invited) do their best to present, they say, "art which tests the line between goodand bad taste." There are some bad jokes and puns, such as Lester Caprasecca's "Watch out for that . . . splat! Skunk"-- a splat of black paint sriped with white; or "Palate, Palette," a violet suede tongue emerging from the wall by Cindy Caprasecca. But there is little bad taste. and much purevisual entertainment.

Al Nodal, director of the Washington Project for the Arts, has sandwiched photocopies of his rave reviews between sheets of plastic, engraved with "Al Nodal Bibliography, 1978-80," while James Faust of Indianapolishas made an intriguing Dadalike collage titled, "I Can't Sleep So I Think I'll Read." Bob Wade of Texas, remembered forhis giant cowboy boots, goes to the other extreme in a tinyboxed assemblage called "Texas Survival Kit," which features Chili, Jack Rabbit Milk and less savory items.

Downstairs, in stunning contrast, high sophisticate Frank Stella is showing his most beautiful prints to date, "Polar Co-ordinated," shown at the art fair last spring. All this and Mohr -- a Patrick Mohr Installation, that is -- continue through Aug. 16.

A spirited new gallery, with the strange name of (the) Olshonsky, has opened in in handsomely renovated spaceat 1811 18th St. NW, in Adams-Morgan. Though no clear direction has yet emerged, two good, young contemporaries are currently featured. If future shows sustain this level, (the)Olshonsky will be a welcome addition.

Mark A. Nelson, assistant professor of art at Northern Illinois University, isshowing mixed-media works that have the look of dinosaur fossils. To achieve this look, Nelson paints on paper prepared with gesso, bulding it up into highly textured, sand-colored surfaces. pThe fossil-like forms are then incised. The work is well-made and holds a technical fascination, though content is then. A few drawings -- notably one over the fireplace -- suggest that this able artist can be more interesting when less preoccupied with media.

But the drawings of Paul C. Martyka stand out here. With mere graphite on a white ground, Martyka first meticulously creates rocky, lunar-looking landscapes, and then goes on to displace and rearrange their imagined geology. The results are highly provocative, patterned abstractions loaded with earth-like implications, reinforced by titles such as "Strata: Raised Beds" and "Displacements, Second Sighting." One would guess that after this debut, this young artist will swiftly be launched into higher strata in the art world. He currently teaches at Winthrop College in Rock Hill, S.C. The show continues through August.

As one of the leading photography dealers in the country, Gerd Sander is constantly confronted with the portfolios of aspiring photographers -- 10 each week on the average. Though the process is time-consuming, and most of the work turns out to be of insufficient quality, Sander says he feels a commitment to view unknowns. The current group showat the Sander Gallery, 2600 Connecticut Ave. NW, presents 15 lucky photographers plucked from last year's crop. Their work makes a strong case for the vigorous good health of theart.

Some of these names are not altogether unknown, notably former Washingtonian Paul Tilinghast, whose six dreamlike fantasies are the strongest works in this show. GeoffreyJames, a Canadian also makes a strong showing, with haunting scenes of gardens from all over the world. Briggitte Burgmer of Germany toys with reality by incorporating real and painted figures into the same frame, while her fellow countryman Michael Ruetz renders in color -- and with appropriate awe -- the Swiss landscape. Bostonian Lauren Shaw is superbly represented by a probing closeup of her mother.

Sander hopes to make this new-talent show an annual event, but warns that he will not be viewing portfolios again until next year. This show continues through Aug. 16, when the gallery will close for two weeks.

Though Washington seems to be overrun with galleries these days, newcomers, often don't knowwhere to start when it comes to buying good -- but not necessarily big-name art -- at modest cost. The Bader Gallery, 2001 I St. NW is always a good place to start.

The current show features a varied trio of artists, among them Swiss printmaker Agass Baumgartner, whose sophisticated abstractions could not be more unlike the Africa-inspired sculptures ofJamaica-born Mike Auld, who wrests icons from cast-off bicycle parts. Auld, whose "African Sculptural Playforms" have just been shown at Howard University, is currently designingplayground sculpture and equipment for a jogging park, using themes from American Indian and black American life. It would be hard to imagine a more perfect match of artist and task.

The four-color etchings of Carole Sue Lebbin, head fNOVA's printmaking department, deal with places where most people would rather be -- Nantucket and the Caribbean among them. Despite their sunny circumstances, there are oddly mysterious overtones enveloping these images of houses againstthe sky. It is this intangible sense of mystery that carries these scenes beyond the ordinary. The show closes Aug. 16.