The stacked tower of four teens holding up a fifth who's spray painting an out-of-reach space is almost as startling to come across in the Carnegie Museum of Art as it would be on the streets at night.

It's part of an edgy, energy-infused Carnegie International installation by Barry McGee, the San Francisco artist who has earned a national reputation within graffiti and gallery worlds. Featured recently in the applauded PBS series Art:21, he'll be at the Carnegie tomorrow for a free evening that will include bands and videos in the Sculpture Courtyard (rain location Carnegie Music Hall).

McGee was born in 1966 in California and earned a bachelor's of fine arts in painting and printmaking at the San Francisco Art Institute in 1991. But he had become part of the subterranean art world by his late teens where he was known by his tag name "Twist."

His International piece is both playful and pointed, a construct that skillfully dissolves lines between street and museum art, calling distinctions into question. McGee told Art:21 about hearing the same people at a gallery reception praise his work and then walk outside and disparage street graffiti, calling for its erasure. "And it'd be my tag. I like that; that's funny to me."

Politically, he challenges mainstream thinking about public space and access to it, particularly by commercial vs. individual interests. "The billboards are very subversive, and advertising is very subversive, whereas most of the stuff that's done on the street is very close to the truth."

The evening begins at 8:30 p.m. with a conversation between McGee and Douglas Fogle, Carnegie International curator, about the artist's work and his response to the exhibition's title, "Life on Mars."

Following will be bands Japanther (Brooklyn-based noise-rock), Extreme Animals (Pittsburgh/San Diego party dance band for Paper Rad) and Pittsburgh's Centipede E'est. DJs Edgar Um and Cutups, and videos by Paper Rad, will keep the night moving.

Information: 412-622-3131; or www.cmoa.org.

ISO: Museum directors

Director Richard Armstrong's announced year-end departure from Carnegie Museum of Art comes at a time when the number of leadership vacancies at U.S. museums is at its highest in 15 years, according to Millicent Gaudieri, executive director of the Association of Art Museum Directors.

Among prominent institutions with open directorships are The Metropolitan Museum of Art, Philadelphia Museum of Art, Solomon R. Guggenheim Museum, and the Hirshhorn Museum and Sculpture Garden, according to a June posting by the Association, which also lists the Carnegie.

Gaudieri says the cause is "mostly generational," with many of the directors reaching retirement age, and notes that with so many desirable openings, it will be a challenge to find individuals with the necessary qualifications to fill the positions.

Career advancement and retirement are two givens that affect turnover in any profession.

But maybe it's time to look at other factors that may be at play in larger to mid-sized arts organizations.

Fundraising, in one manifestation or another, is a significant skill that a director must possess, in addition to being well versed in the subject matter and cultural milieu of his or her institution.

Though individuals vary, one must presume that the initial attraction for people who devote their lives to the success of an arts organization is the art itself, and not the bureaucracy.

As economic times worsen, and costs increase, a larger percentage of a director's effort frequently must go toward ensuring an institution's solvency, leaving a smaller percentage of time to attend to the work that originally attracted him or her.

Again, circumstances differ. But for the long-term health of the institutions we enjoy, it may be time to reconsider the model.

One step is to institutionally articulate -- in staff and board meetings, for example -- the accelerating demands and hours they consume, and adjust the mission accordingly. Examples that some organizations have adopted, here and elsewhere, are to decrease the numbers of exhibitions held annually and to take a measured approach to facility expansion.

Allowing directors -- and perhaps other critical staff -- opportunity for renewal may be another way to maintain institutional vigor. One of Pittsburgh's major foundations might, for example, establish a sabbatical program of six months to a year that would be awarded dependent upon merit and need.

Many area institutions have achieved national acclaim because of the director's vision -- and 24/7 commitment. Such competence and dedication are qualities that all concerned should strive to hold on to.

While change is at times the best solution, many directors love what they do, are good at it and gain from experience. Sometimes administrators simply need a break.

As to the current national situation, it will be interesting to follow whether the opportunities available result in more women being hired by the larger institutions. Gaudieri says more than one-third of the association's membership is female, but most of those continue to head mid-sized to smaller museums and university spaces.

By the by, it could be noteworthy that the last male Carnegie International curator before CI08's Douglas Fogle was Armstrong in 1995.