I am thinking about doing a supernatural marathon. I'll try to get season 1 through current and see how it goes. I did that with breaking bad, but that was just 5 seasons. We are talking about 10 seasons with Supernatural. That's going to take at least 3 weeks if I plan to have a life outside of the house.
I haven't watched the TV series, although I've watched the anime version of this. It's only a few episodes long (a little bit over 20 if I remember correctly) and it's not as elaborate as the TV series, but it's still good. I came across it on Youtube so if you want to check that out you'd surely find it there.
I was hooked on Supernatural last year and I was able to get through five seasons before I just completely lost interest in the show and stopped watching. Maybe I'll go back one day and try watching the series from the beginning again. But Vampire Diaries is dark enough for me at the moment.