a) Good conversation
b) Word games, with pencil and paper,
there are several that can be fun, like 'taboo';
the relative cards can be made on the fly,
if you have a book (novel) in your hands to find inspiration
Here are the rules, believe me it's fun! :
www.ehow.com/how_6859639_make-own-taboo-cards.html
en.wikipedia.org/wiki/Taboo_%28game%29