Who in America will benefit from a government shutdown?

Republicans, mainly the new Tea Party caucus in the House of Representatives, seem determined to either defund the Patient Protection and Affordable Care Act, or refuse to raise the debt ceiling. If we do not raise the debt ceiling, that means the US Government will not be able to meet the budgetary obligations the Congress has already set for it. Bond rating agencies will certainly lower our credit rating if that happens, meaning the cost of interest on our debt will shoot up. Who wins from all this? Is it just that Tea Partiers are mad as Hell, and determined to shoot themselves in the foot to prove it? Or is there some sinister group that will benefit from the suffering they inflict on the rest of the country?