Also see:
and this nice list in Wikipedia:

California Split A minor bureaucrat in Riverside California made some headlines last week when he suggested California should split itself into two states. This isn't total secession. The new state would still be a member of USG, just as West Virginia became a state by breaking off from Virginia in the summer of 1861. No one takes this seriously, and they shouldn't, but it leads to some interesting questions. Ilya Somin comments: This is one of those areas where … Read More

via Let A Thousand Nations Bloom