I played on this one server,and it was really enjoyable.It had Capture The Flag,if you held shift in the spawn you can change to diffrent classes,the classes were all diffrent depending on the map.There was a pirate ship map,a halo map (with actual guns no spout) and another map that was Sumo (everyone had hoes and they had knockback)
http://www.minecraftforum.net/topic/1472633-sip-server-mature-admins-also-read-if-your-new-to-mc/page__hl__+gmangavin