One or more developed countries will see significant civil unrest due to ongoing problems with the economy (50%).
This is the sort of thing I was thinking of and expect to see more of.

Haven't riots been going on in Greece pretty regularly? (eg, 11/2009) Did you put at 50% the chance that the riots in Greece would stop? Maybe it was reasonable to put at 50% the chance that the riots would stay at 2009 levels and 50% the chance that they would go back to 12/2008 levels, but it's not clear that "significant" should mean that.
I would like to propose this as a thread for people to write in their predictions for the next year and the next decade, when practical with probabilities attached. I'll probably make some in the comments.