Guys, there are rumors for a second season coming out in 2016 (not sure about 2015) but still nothing is confirmed.
Also there is a movie coming out in November 22 entitled Attack on Titan: Guren no Yumiya cutting down the first 13 episodes in the series. There is also a second movie to be released in 2015-Attack on Titan: Jiyuu no Tsubasa for the rest of the episodes. Moreover, there is going to be a live-action one in 2015 as well.
So far, there are 25 episodes (first season) and 2 OVAs with a 3rd one coming out in August 8.
The first OVAs is called "Ilse's Notebook" and takes place after the 3rd episode of the series. The second is a crack OVA based on a chapter Isayama wrote for the laughs. The third one will be about the 104th Trainee Squad.
Also there are some chibi episodes coming with the bluray releases, "Chibi theater: Fly, cadets"
Edit- yes, OVA stands for Original Video Animation (:
























