Human Brain Cloud is a massively multiplayer word association "game" by Kyle Gabler, who described it as such:
The idea is that given a word, a player types in the first thing that comes to mind and the results are combined into a giant network.
For instance given the word "volcano", a common word people might submit would be "lava", and this would result in a very strong connection between "volcano" and "lava". On the other hand, given the word "volcano", fewer people might associate it with something like "birthday party", resulting in a very weak connection or no connection at all. Over time and with many players, I hope the cloud will gradually grow to represent words and phrases people tend to associate with other words and phrases, assuming it doesn't get inundated with spam. The cloud started with just one word, "volcano". All other words were submitted by visitors to this site.