Would it be possible to have an object like a power-up or piece of equipment that when picked-up does not affect the player but runs a simple script. (Script only needs to perform one line other than the line required to start it)

I have looked through the scripting bible but I didn't see any thing but I could have easily passed over it.

Well it would go something like this:
if cammo is picked up
awake script

This is not possible. You would need to put a trigger volume where the powerup is located, and have the script run when the player enters that volume.