I am a huge fan of this series. It's 145 episodes long and it has everything that makes a shounen anime successful - EPICNESS.
Plot Summary:Kobayakawa Sena is a little guy who always get picked on by the bullies in school. Since elementary school, he always play the role of the 'errand boy' to the extent that he has become swift and fast in his movements. Coincidentally, Hiruma Youichi and Kurita Ryukan are looking for a fast running back for their American Football team (Amefuto) and want to put Sena in the team. To hide their new 'star' player from the eyes of other High Schools, Hiruma encases Sena in a Amefuto helmet with a dark visor and name him Eyeshield #21. ANN
Of course the team then goes on to tournaments and meet new teams and stronger challengers. There is quite some character development throughout the series which left me very content with it. This anime is quite under rated - I have no idea why. I mean, yes, the animation might not look very great but I have to say, this show ranks with the best sport animes out there. The first couple of episodes may not be very interesting but you will be hooked after the first match. This is a thriller anime which will leave you hanging at the edge of your seat and screaming at the computer screen.
I would really recommend this anime if you're into sports animes such as Captain Tsubasa, Prince of Tennis, Slam Dunk etc.
This anime consists of comedy, tactics and some drama. Above all, it consists of epicness D=