Aww, I adore ferrets.

A few tips:
Both of my ferrets love having piles of old towels and clothes to burrow in, it is always the first thing they run to during out-of-cage time. And like Karen said, anything that is noisy usually goes over well, too. For treats you could try a small amount of cooked egg(hard-boiled is a favorite around here).
If there is anything specific you would like to know, feel free to ask.

Hopefully an owner is found, but it is good to know that in the meantime he has a nice place to reside.
Good luck!