How to prepare an easy and fast snack rich in protein? I'm going to the gym, usually, everyday. I'm looking for a simple and easy snack, something that I can carry with me to work, to the office, and would help me to recover from my workout. :)

I know some recipes rich in carbohydrates but none rich in proteins :(
(Besides whey protein, of course)

Any tips or recommendation ? 
Thanks in advance!
A hard boiled egg is high in protein and comes in a handy natural container.