In fact, there is so much Harmony of the Seas entertainmentthat trying to fit everything in during your cruise could be a challenge. 1. With rock and roll favorites like Summer Lovin and Greased Lightnin and a star cast of performers, you might just feel like you are reliving your high school days at Rydell High. This is the ideal place to spend the day, whether youre a beginner or a pro. //