Messier marathon is an attempt to find as many
Messier objects as possible during one night. The number of visible Messier objects varies depending on season and the location of the observer. At a latitude close to 25 degrees North it is possible to observe all Messier objects in one night.
http://www.seds.org/messier/xtra/marathon/marathon.html (http://www.seds.org/messier/xtra/marathon/marathon.html)