My Business English students often complain that the most difficult part of using English in their jobs is not making presentations or chairing meetings but the networking, chatting and bumping into people in the lift that can happen before and afterwards. There are also lots of cultural issues involved in starting and ending conversations, getting down to business, suitable topics, etc.
Luckily, though, all of that is not only eminently teachable, it also makes for fun communicative practice in the classroom. Just put together a list of my materials on the topic, including some linking it to common grammar points such as question formation and different tenses:
Small talk photocopiable classroom activities page
and I’ve now published an e-book with over 100 pages of suitable activities:
TEFLtastic 