TOPICS:
DISCLAIMER
There are quite a few sugar glider sites out there with a lot more information than this page has.  If you are thinking about getting gliders, be sure to do some research first and obtain information from several different - preferably reputable - sources.  Also, keep in mind that gliders are not legal in all areas.
BACKGROUND
Sugar gliders' scientific name is Petaurus breviceps.  They belong to a group of marsupials called the lesser gliding possums and are native to Australia and New Guinea.  They are arboreal (live in trees) and omnivorous (eat plants, insects, and animals).   Unlike American opossums - and luckily for us - they produce only one or two babies at a time  instead of ten or more.
HOUSING
During the warmer months, our guys have the run of our large, screened-in porch at night.  They love climbing the stucco walls and the screens and have a great time catching bugs - including the occasional scorpion, which they seem to view as a delicacy.  The Zebra finches live on the screened-in porch in the daytime, but after I observed Dextrose trying to reach through the bars of their cage and grab one, we started putting the birds in the laundry room at night.   Since Zebra finches are native to Australia, I guess it's possible they may be prey for wild gliders.
During the winter, they occupy our fully-enclosed porch, which is equipped with an electric heater.  Their daytime home base is a cockatiel nest box inside a ferret/rabbit cage.   Once they are all in bed, we close up the cage and put it in a closet.  They like to sleep all wadded up in a big heap in the nest box with the gliders at the bottom of the heap completely buried under the gliders on top.
Gliders are such active, busy little creatures I can't imagine keeping them in a cage all the time.  It wouldn't be fair to them.  A lot of people let them freely roam their houses, but that isn't an option for us because we need to keep them separate from our cats, who would eat them like popcorn if given the opportunity.  They don't seem to have an instinctive fear of cats, either.
DIET
The largest portion of our gliders' diet consists of insects; some they catch on their own and others we buy.  They also eat small amounts of dry cat food (the "light" variety), some fresh fruit, vegetables (except lima beans, which all animals, including small children, seem to loathe), the occasional piece of pasta, and Zebra finch eggs.
I get the impression that a lot of people feed too much fruit and not enough insects and other protein sources.  This can cause serious problems, including calcium deficiency, which may be linked to an often-fatal condition called Hind Leg Paralysis.
VOCALIZATIONS
Gliders can be surprisingly loud, considering their small size.  The most common sounds they make are barking and what we call cursing. 
Barking sounds very much like a small dog yapping, except that there are evenly-spaced  pauses between barks rather than constant yapping.  Both male and female gliders bark, and usually, only one of our gliders barks at a time.  Only once have I heard two barking simultaneously.   Why they bark, I don't know.  People have theorized that they are advertising their presence to other gliders, perhaps as a warning to stay out of their territory.   Most of the time when one of our gliders is barking, the rest stand very still, as if they are on the lookout for something.
Cursing is more commonly referred to as crabbing, but to us, it sounds more hostile than run-of-the-mill crabbiness.  It is indescribable:  You just have to hear it.  Our gliders virtually always curse if we open the top to their nest box when they are inside it.  Frequently, all six curse at once, making quite a racket.  No doubt a predator hearing this noise might be startled enough to move on in search of less surly prey.
UPKEEP

Gliders are not low-maintenance pets.  They can't be litterbox trained, so daily clean-up is necessary.  Ours enjoy flinging bits of food all over the place, too.  They are bright, curious little creatures who will get into everything, if given the opportunity, plus, they have opposable fingers, which means they are experts at untying knots and performing similar tasks.  They shouldn't be allowed access to anything with which they could hurt themselves, and the area in which they live should be thoroughly escape-proofed.

Gliders don't require vaccinations, but if they run into medical problems, you'll need to find a vet with glider experience, which may be easier said than done.  The two treatable conditions we've run into so far were Pocket's and Geri's problems.  
PROS & CONS

Thinking of acquiring gliders?  Here are some pros and cons, from my point of view:
PROS:
  • They're really cute and fascinating to watch.
  • Their potential lifespan is around 10 years, which is unusually long for small, furry animals.
  • They breed readily in captivity, which is a pro if you want babies.
  • They don't require vaccinations.
  • Apart from bugs, they eat food that is easy to obtain and reasonably inexpensive.
  • Males can be neutered.
CONS:

  • You'll need more than one.

  • They are on the slovenly side.

  • It may be tough finding a vet who has any experience treating them.

  • They may not be legal where you live.

  • You'll need to buy or catch bugs for them.

  • They are escape artists.

  • They breed readily in captivity.  Be prepared to shell out some money to neuter your males, if you can find a vet who can do it.  It cost more for me to have a glider neutered than it did to have a male cat neutered.

  • If you want to sell them in the U.S., you'll need to get a federal permit.

  • They are nocturnal, so you will probably be asleep during their most active hours.

  • They need to be kept apart from most other pets.