The Needham Education Foundation, a community nonprofit that awards grants to support the local schools, will hold its 22d annual spelling bee Wednesday at 7 p.m. in the Needham High School gymnasium. More than 50 teams of parents, teachers, middle and high school students, and business and community representatives are signed up to compete in the foundation’s biggest annual fund-raiser. Admission is free, but commemorative hats, T-shirts, and cupcakes will be available for purchase. The roster of celebrity word readers includes Gary Gillis, a former WHDH-TV newscaster; Olin College president Richard Miller; and Mike Riley, Lowell Spinners announcer. Last year’s winning word was “samizdat,” a term from the Soviet Union involving the dissemination of censored materials. For more information, visit www.nefneedham.org.