Ok, the current MOTM voting system is so primitive that it almost makes me cry. Its subject to peer pressure, off topic discussions, and never turns out more than a handful of votes because its not user friendly. So I propose a radically different system.
Create a new page dedicated to voting for MOTM. Inside this page are all the maps from the corresponding month(listed dynamically accoring to submission dates, of course). Each map listed can be linked to the matching map in the vault. Under each map lies a check box of which only one can be selected, and a "VOTE!" button at the bottom of the page. Once a vote is cast, a database logs the user who cast said vote so that if the user votes again, his vote is changed, not added.
Something like this: