What if Obama loses the electoral college votes on December 15?

I know that Barack Obama is our president-elect. I know that the votes that decide our president are the electoral college votes and that will happen on December 15th. The constitution of some states requires the electoral college to vote according to the popular vote, but many do not. If the electoral college is not legally bound to vote the same way as the popular vote of their state, they are free to do as they wish. So, my question is even though he won by popular vote, do you think it's possible that Barack Obama could lose the electoral college votes on December 15th?