The New York Times Blog "The Upshot" has a cool feature - it's called 'you draw it' and shows the first half of a trend graph, and invites you to draw the second half with your mouse. It's a great test of what you think you know about current issues. For example, one is a chart of the number of deaths from HIV, the part of the graph you can see shows the years from 1968 to 1990. You then draw the line from 1990 onwards, and it then reveals the actual data. Finally it shows all the data together in a chart of selected causes of death. The results may surprise you. But the reason I like this so much is because, as a confirmed data nerd, I hate the idea of making a mistake based on something I think I know - when in fact the truth is different. I haven't included any pictures because, well, that would spoil the game if you wanted to play: do try it, only a two minute read. Link.