Freudenspiel is a compound word that literally translates to "joy-game" or "game of joy". It's a less common, more poetic word than simply saying "joy" (Freude) or "fun" (Spaß).
In the context of the song, it evokes the idea of immersing oneself in a playful, exhilarating experience driven by music and emotion. It suggests a vibrant, almost theatrical engagement with happiness, making it a memorable and enticing word for learners.