Friday-Saturday. The Ars Nova Singers are known for putting together programs that are both entertaining and well-researched. That’s the case this weekend, when they return for the season with a concert built around Sergei Rachmaninoff’s “Vespers,” among the most revered pieces of choral music. Rachmaninoff composed his famous work in 1915, just two years before his family fled the political upheaval taking place in Russia. The piece, which partly borrows texts from the Russian Orthodox Church’s “All Night Vigil,” was suppressed for years by the communist government of the time. Two performances: 7:30 p.m. Friday, St. Paul’s Lutheran Church, 1600 Grant St., Denver, and 7:30 p.m. Saturday, First United Methodist Church, 1421 Spruce St., Boulder. $25. .
