Call of Duty has zombies, why not Battlefield? The campaign has enough humor to balance it all out. And with better connections and more teamwork (medics throwing health, assault throwing ammo), and would sell ALOT. Start with 5 maps, make them smaller than the regular maps. Have a nice big building, with windows and destructible walls and such. Put some turrets and MAYBE small vehicles such quads. Add melee and new melee weapons (sickles, sledgehammers), and you have a complete package!
I am being serious. This may sound silly to some of you. But I would LOVE to see some kind of Battlefield: Zombies in the future! Make it cheap too, maybe $9.99 or $14.99 and then release new map packs containing new weapons and maps for $4.99. Cheap, glorious fun!