this is a small one but i think good for RP and can have a tactical use
players could craft horns (ie the type u blow) with different pitches (could be down to material its crafted from, or maybe a user defineable setting on creation)
with different pitch sounds one horn could be distinguished from another and players could use them as a signal for attack or to call others to their aid (i know this can be done in the chat window... but how RP is that?)
