In all seriousness there is two kinds of downtime. On the floor and on break. On break pretty much anything, TV, internet, books etc. On the floor electronic devices are prohibited(but not entirely absent). When there are others present it is generally just BSing all around. As controllers you have to be pretty thick skinned because often this ends up being a good-natured bully-fest on someone over something stupid. (ie: Last week it was my black socks with jeans). When you are on a mid you try and find anything to keep your mind occupied, books, drawing, some people do homework for college classes they are taking.