It's a credit to the Glee cast, crew, producers and musical numbers that the show has remained so popular despite its unusual scheduling.

First, it premiered a single episode in May 2009. Fans were then forced to wait until September for a true first season.

Now, it's taking the longest hiatus a series has ever gone on mid-season. It won't return with new episodes until April.

Fortunately, Fox recognizes this problem and has taken yet another unique step: it released a DVD this week of just the first half of the show's first season.

Titled "Road to Sectionals," the four-disc set includes 13 episodes and a few special features. They are:

• Welcome to McKinley: Principal Figgins-featured video that introduces new students/viewers to the school. 
• Audition Clips: Full-length videos for Rachel's "Respect" and "On My Own" renditions.
• Casting Sessions – Crew members and cast members discuss the origins of the show, as well as the casting process for various characters.
• Deconstructing Glee with Ryan Murphy: The creator analyzes the themes behind the show.
• Dance Boot Camp: The Glee choreographer and many actors focus on the musical numbers and provide backstage footage from the dance practices.
• Meet Jane Lynch: Self-explanatory. Hilarious.
• Video Diaries: Many of the cast members share video diaries they shot during promotional appearances for the comedy.

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.