What tv/movie series did you last had a marathon on?

With Netflix, it is easy to just binge-watch. The last series I had a marathon on was "Grimm". Actually, I've been a loyal follower of the series but I've been busy when the latest season came out. Recently, I had some free time so I watched all the episodes I've missed (about 11) in a day and I have currently caught up to the present episode. Other series that I would love to binge-watch would be older series that I wanted to watch when I was a teenager but never got a chance like "The O.C" and "Buffy the Vampire Slayer".