The Heritage Provider Network is offering a $3 million prize for an algorithm that can predict future hospitalizations based on patient data. This seems like a very cool application of machine learning. If I knew more about machine learning (or anything, really :P), I would totally participate. This sort of application would be invaluable to the health care field. Imagine having the ability to predict future problems with a patient, years in advance. That would cause a huge improvement in the quality of life.
If any of you know anything about machine learning, you should try out this challenge. It's set to start around next year. You could make a huge difference in the quality of life of people. I suppose $3 million would be nice as well. :P