To celebrate National Chamber Music Month, Brightmusic Society of Oklahoma presents an ambitious four-concert Bach and Brahms Festival, with a different program each night. Concerts are scheduled for 7:30 Saturday, 4:00 p.m. Sunday, and 7:30 p.m. Tuesday and May 31, all at St. Paul’s Episcopal Cathedral, 127 N.W. Seventh. Admission is $10, or $30 for a festival pass. Visit brightmusic.org.