The Socialist Workers Party recently announced that one of its members is a write-in candidate for Mayor of Chicago.  He is John Hawkins.  As far as is known, he is the only person running for Chicago Mayor who is not a member of one of the two major parties.  Hawkins is a write-in candidate because he did not submit the needed 12,500 signatures to get on the ballot.  The election is February 22, 2011, and is officially non-partisan.

In 1975, when Chicago Mayoral elections were partisan, the Socialist Workers Party placed its Mayoral candidate on the ballot.  She was Willie Mae Reed, and she was the first minor party candidate to get on the ballot for Mayor of Chicago since before 1931, the year the legislature set the petitioning requirement at 5% of the last vote cast.

In the 2011 election, six candidates for Mayor submitted petitions and were not challenged.  They are Danny K. Davis, Miguel Del Valle, Gery Chico, Patricia Watkins, James T. Meeks, and William Walls.  Another nine candidates submitted petitions and are being challenged.  A few others submitted petitions but then withdrew or have already been declared to have insufficient petitions.  UPDATE:  on December 23, James T. Meeks, a State Senator, withdrew from the race.

For City Treasurer, only two candidates submitted petitions, and both of them are being challenged.  See this article about the two petitions in that race.