Michigan will hold a special election to fill the vacant U.S. House seat, the 11th district seat. The seat is vacant because Congressman Thad McCotter resigned suddenly after his petition to be on the Republican primary ballot was found insufficient. He could have run as a write-in in the August primary but he chose not to. See this story. The special election will be November 6, and the term will be for only two months.
The U.S. Constitution does not permit anyone to serve in the House unless that person is elected. Thanks to Thomas Jones for the link.