client
Mwheelup()
eye = locate(x,y+1,z)
Mwheeldown()
eye = locate(x,y-1,z)
This would be called upon when the mouse middle button is scrolled up or down. Or of course on laptops their scroll on the touch pad aswell.
They would act as client commands, just as if you have South(), West(), etc. It would allow new possibilities for BYOND games, for spectating games you could move up and down the map with it, and for RPG games for example, you could scroll through items in your inventory. Just something I'd like to see.
Edit: Another possibility for this that popped into my head is for the game Proelium. It would switch through your weapons for you.