
One really fun event is the Feria Yucatán Xmatkuil 2010 which will be taking place November 12 through December 5. Read more about the feria here,
or here.
Public transport from Centro (Calle 69 entre 58 y 60) will make the trip quick and easy, and pretty darn cheap at 6pesos each way.
Entry was 12pesos in 2009 (if I remember correctly...)