Ooh, this is a tough one! What's your all-time favourite play in Eyeshield 21? I'll trust that I don't need to provide a definition of what a "play" extends to for the purposes of this question (although I have a feeling I'm going to regret this), but I will specify that I'm asking about a single whole play, not a string of them, or anything as limited as a single action from one.
Personally I can't choose yet. My main candidates are:
*Devil Bats vs Nagas: Dragonfly play; Unsui hands off to Sanzo, Sanzo turns and backpasses to Agon, Sena (marking Agon) fumbles it at light speed. Monta goes for it, but is chased by Ikkyu and several Nagas, Kurita uses "Final Attack: Kuri-Hammer" to flatten everyone. Jumonji passes Hakkai with Juvenile Delinquent Murder Method, picks up the ball and runs. Agon pursues, catches him just outside the endzone and Jumonji drags him over the line- touchdown.
*Devil Bats vs White Knights (1st match): Final attack; Kurita flattens Otawara and unbalances Shin, Sena breaks through the center. Shin pursues, Sena hits light speed for the first time and outruns him- touchdown.
*Devil Bats vs Nagas: Sena blitzes Unsui when he was supposed to be marking Agon, fumbles ball, picks it up and runs. Agon pursues and chops Sena, Sena counterattacks then passes with Devil Bat Ghost. Agon comes around for another attack, Sena pushes down from Agon's blind spot and drives him face-first into the ground then runs on- touchdown.
A lot of the best plays were from the Nagas match, but some of my other favourites include the second last play of the Poseidons match (when Sena beats Kakei but is caught by Mizumachi) and the highly convoluted first appearance of the Juvenile Delinquent Murder Method in the match against Taiyo. I'll decide on a personal winner shortly- what's your favourite?