Style Blog: 'Glee' rings in 100th episode by focusing on the past: Here's every song the cast reinvented

Fox's "Glee" burst onto the scene in 2009; five years later, it barely made a blip on the pop culture radar as it celebrated its 100th episode. Perhaps sensing it's not the groundbreaking force it used to be back in the day when it spawned an era of singing shows, the writers wisely took the opportunity to gaze back into the past at the glory days.