Reborn! –Episode 37 "Teacher and Student Combination, Assembled"

All of them are going through training by their respective tutors, whch as:

Tsuna is being trained by Reborn,
Yamamoto by his father,
Gokudera by Dr. Shamal,
Ryohei by Colonello and
Hibari by Dino.

Althouhg they all train in a different ways, but their main objective is to defeat the Varia family!