Steve:
Draw. Since he's has been to drawing school, and you want to learn he teaches you.

Clint:
Archery. Kinda obvious.

Bucky:
Play games. Whether it's checkers, monopoly, scrabble, or cards. Be careful of cards....he likes strip poker.

Loki:
Read. You read to him and he reads to you!

Thor:
Cook. He doesn't know much since he was raised in a palace but is willing to learn. His favourite is cookies and cake!

Tony:
Party. Well mostly just the two of you dancing and singing.

Bruce:
Science! You both are nerds, what better way to bond then science!

Pietro:
Movies or video games. You cuddle while watching movies and yell at each other when playing games.