Worldmapper

This site is really interesting, especially if you have students who are quite politically aware (or you feel you'd like to make them more politically aware!).  It has a wide range of world maps that are distorted according to various criteria.  You can choose what you'd like to see -anything from numbers of people in tertiary education to internet use, and a whole raft of other things.  Below is an example of one showing GDP, showing how the purchasing power of various currencies varies form country to country and therefore the discrepancies in power between nations. It's a bit of an eye-opener....

I think that this would work very well with educated teenagers or adults who are interested in world events.  A simple print out would make a great warmer for a discussion on the topic and could be used for work on comparatives and superlatives, too. If you were teaching articles with geographical place names, it might make an interesting alternative to the 'take a trip round the world' activity, too.

I suppose that the only limitations are that the class would need to be fairly well educated and have a good sense of the actual geography of a world map (this wouldn't work so well with my ESOL class of middle aged South Asian women, I don't think) and that they need to have a background of expressing the kind of critical thought that this discussion would entail.