I participated in one of these for the first time last night with the local astronomy group here. It was their 11th annual marathon. A welcome break from the intensity of imaging. Sometimes we forget what got us into this hobby! Anyway this is a very interesting and enjoyable activity which many amateur groups participate in. There is no grand prize or anything in our group for finding all 110 in the same night but a great time with like-minded colleagues engaging in the "thrill of the cosmic hunt". We had a pot luck dinner an hour before sunset, set up the coffee thermoses, then several group members set up their various refractors and dobs. I assisted with operation of the club's observatory scope which is a 16" Meade and piggybacked 100mm Williams Optics refractor with Mallincam Extreme attached, housed in a roll-off roof structure. We use the equipment mainly for outreach events here at the Leasburg National Park, about half hour north of town.
I never really knew much about how this Marathon worked practically speaking but there is a lot written about it. To find all 110 objects in 1 night you do have to do your homework. There is only a small window of days where this can actually be done! It turns out that between lattitude 20 and 40 you can only realistically accomplish this at the end of March. There is a well-known sequence of objects which Marathoner's know about which enables you to see all 110. For example we started with M77 and M74 low in the west, then went over to M31 and M33 before making our way east. Of course we did have the goto capabilities of the main observatory scope but ran into glitches such as the roof obscuring a few of them and having to work around preset slew limits! At any rate I learned a lot about the layout of the Messier Objects and we got some great views of many of the classics and some I never really knew much about. M46 for example has this really cool planetary nebula embedded right in the middle! All in all a great experience and a lot of fun.
I would be interested to hear of others' experiences doing this!