Native playwrights don't get enough publicity, so here's a corrective:
One Native playwright worth mentioning is William S. Yellow Robe Jr. Of Assiniboine and African-American descent, he's written such plays as Better-n-Indins and Grandchildren of the Buffalo Soldiers. The former presents a series of sometimes-funny skits, while the latter deals with mixed-race issues.
Another notable Native playwright is Hanay Geiogamah (Kiowa). According to the Native American Authors Project, he "is known for plays in which he employs humor, realism, and idiomatic language to subvert negative stereotypes about Native Americans and to address the alienation felt by Indians in contemporary American society. He has taught at Colorado College, the University of Washington and the University of California at Los Angeles, and is one of the founders of the American Indian Theater Ensemble."
Diane Glancy, of Cherokee and English/ German descent, has won numerous awards for her poetry, prose, and plays. She has been an artist in residence for the State Arts Council of Oklahoma and a graduate of the prestigious University of Iowa Writers Workshop. She now teaches Native American literature and creative writing at Macalester College in St. Paul, Minnesota. According to a website, her work shows how "traditional [Native] values and ways of life interact and are juxtaposed with those of modern America."
Other up-and-coming playwrights include Rhianna Yazzie, Bret Jones, and Carolyn Dunn.
For more on the subject, see Native Plays and Other Stage Shows.