I got just a nice idea. Why we dont start a war server?
You have 2 - 4 teams, you have team bleu and team red. (Team yellow and green if there are more teams.) You fight versus you enemy the other minecraft players. You can uses dynamites swords. And make of you minecart a tank!. You can place hidden landmines in bridges. You can make you little base bigger and safer.It should be very cool and funny to do. You can also add minigames in like capture the flag or destory their base and/or kill their leader. Or you get for every kill 5 points. The first team with 100/250/500/1000 points wins. Maybe if Notch read this he can add some extra funtions to make this possible.
Did I need something to add or I forget something, please let it me know!