Celtic-and-beyond duo Siusan O’Rourke and Zig Zeitler entertained a small but enthusiastic lunchtime audience on Friday for the second in AnnArbor.com's Summer Concert Series.

The two performed Celtic and world music duo, combining strong vocals with a broad mix of instrumentation. O'Rourke and Zeitler have been bringing their music to fans of traditional and Irish music at festivals, special performances and workshops throughout the United States, Ireland and Puerto Rico.

The two own the White Crow Conservatory in Saginaw. While Irish music is their specialty, other influences are present; for example, Zeitler has released an album of original bouzouki tunes. They play both classics and original works.

AnnArbor.com's Summer Concert Series are free and held from noon to 1 p.m. every Friday on the patio outside the downtown office of AnnArbor.com, at the corner of East Liberty Street and South Fifth Avenue. You are invited to bring your lunch along and enjoy the music on our open-air, covered patio outside our Community Space.

Next Friday's concert features Lisa Pappas & Michael Weiss, a folk duo who perform a eclectic mix of folk-rock originals, alt-country classics, and traditional songs.