Updated Spoiler! The "boys vs. girls" mash-up competition will happen in the upcoming Glee episode, season 4 episode 15, "Girls (and Boys) on Film". You can read an early synopsis for the episode here.
More mash-ups, indeed. What kind of mash-ups this time, you ask?
This time around for the "boys vs. girls" challenge, Finn will have the glee club perform mash-ups featuring movie songs!
"...An upcoming episode of Glee will feature movie song mash-ups as part of another boys vs. girls challenge."
What movies would you like to see the guys and girls mash together for their challenge performances this season?
Source: Entertainment Weekly