I agree with others that OP doesn't have time to leave the airport. But the good news is that MSP isn't a bad place at all to kill time, shop, and just people-watch. MSP has better food/shopping options than most airports with the added bonus that almost everyone that the OP will interact with (even TSA) is actually pretty nice. So my advice is to get some exercise, walk around a bit, stop for a snack or ice cream or something, and the time will fly by.