Hey there,
Sugar gliders and monkeys are totally different creatures.  A sugar
glider is a marsupial.  Like an opposum, but they aren't a species of
opposum.  Here's a link to the Marsupial family tree..
http://www.brainyencyclopedia.com/encyclopedia/m/ma/marsupial.html
 
Sugar gliders look a lot like flying squirrels and are probably an 11 on
the 1-10 scale of pet care easyness.  There's a lot of information on
google for those who are interested.  Because they are small, fragile,
and rodent like, I doubt they would be compatible with ferrets.  Ferrets
probably couldn't resist a taste, either that or when they try to wrestle
with it, their new friend breaks.  Not a good picture.  They run probably
about $100-$200 dollars on average.
 
As for monkeys, I don't know which kind it was that you saw, but they are
a HUGE commitment and are probably like having a toddler that gets into
absolutely everything around (that also turns into a wild animal, and can
cause serious harm).  Here's an article by the national geographic
magazine about keeping monkeys as pets.
 
http://news.nationalgeographic.com/news/
2003/09/0916_030916_primatepets.html#main
 
This link is quite profound.  But be warned, it has graphic images of
what a monkey can do to a human (as in bite, bruise, and beat up)
http://www.petmonkey.info/presentation/Slide01.html
 
http://www.petmonkey.info/index.htm (this has a lot of information)
http://www.ippl.org/apr-03-23.html
http://exoticpets.about.com/cs/primates/a/primatesaspets.htm
 
I am overwhelemed at the amount of negative information i found.  These
sites i listed are the on the first page of a google search on "pet
monkeys" (excluding two or three advertiesments)
 
Here is a link for their care.
http://mimi.essortment.com/petsmonkeycare_rgay.htm
 
From the little bit I've read so far, it doesn't seem like a good idea to
have a monkey as a pet.  Let alone have them near your ferrets.  Monkeys
belong in the wild, not in your home.  That's my stand, but do some
research on your own and decide for yourself.  There's tons of info on
google, I encourage you to look.  I hope i helped!!
 
- Jules
[Posted in FML issue 4695]