Since its first official performance in 1995, Ireland's “Riverdance” has remained an odd kind of entertainment phenomenon, the type that invites a healthy amount of critical skepticism and parody among casual observers. You do have to wonder how an entire production based around stiff upper bodies with tap dancing below equals millions of dollars and sold-out venues across the globe. But once you get past the novelty and actually watch a performance, the show's large-scale reliance on percussive precision is difficult to brush off. After 10,000-plus performances, the famous Celtic export is in the midst of a farewell tour. Playing five shows in three days at the Landmark Theater, “Riverdance” is scheduled to hit Richmond from April 16-18. $40-$60.