This idea is a funding source for the server and a way for players to donate for events that all players can join in on. A simple implementation could be a lottery type even where a message is displayed at normal intervals saying "[sponsor] has sponsored a giveaway! use /giveawayenter [sponser] to enter the drawing!" It could also be epanded to include events like spleef, boat races, chicken races, whatever where the prize is provided by a player donation rather than the server. 

I also think it would be sweet if those who supported events got a unique 'supporter' prefix (if they wanted).