Cirque du Soleil
I had seen bits of Cirque du Soleil acrobatics before, so I knew they were magical, but I didn't realize the shows involve something of a theme (like a play), including vocal performances.
It was amazing.
A bonus surprise was the theatrical debut of Robert Muraine, who I knew as the popper from season 4 of So You Think You Can Dance
An article, with more pics of the show here (includes a video excerpt).