I would tell them to try and stay up for days on end until they can take it no longer and see if they become a zombie themselves :)
From the English Dictionary:
1. a person who is or appears to be lifeless, apathetic, or totally lacking in independent judgment; automaton
I'm pretty sure if you stay awake long enough you to can become a zombie.
As for the raise the dead type of zombie I can think of only two off the top of my head from a Christian stand point of view. Jesus rose from the dead after three days and he also resurrected Lazarus. However I doubt they had the full skin falling off the bone, arms outstretched, empty eyes, etc... look.