I got started being interested in rats when my Dad got me my first job at Everett Community College taking care of the lab rats in the Psych Dept. (Dad was a Biology professor there, so I had a little help getting that job!) It was an eye-opener - rats crammed in tiny cages, barely enough room to turn around. They had males and females together, and they would breed, then there would be mass infanticide as there was no room in the cages for babies.
I separated them all out and got them to give me more cages. They had a huge squirrel cage that I'd put a few in at a time so they could run around and play. At one point there was about 50 rats to take care of. They said I could take one of the geriatric rats home, so I took a beige hooded rat and named him Charles B. Wratt. Sadly, one day I went to work and there were no rats! I asked my Dad if they moved them but he said the Psych. Dept. leader had euthanized them all (put them in bell jars with chloroform.) I was heart-broken, but it was a good learning experience for me, and I've had the little critters pretty much most of my life. I'm rat-less now, as unfortunately they only live about 2-3 years. I seem to need a little breather before committing to a new couple of souls - pet rats should always come in at least a pair as they are VERY social and are much happier with a pal.
If anyone has any questions about getting a pet rat, I'd be glad to help - there are some great Rat Associations around the world, and there are even rat shows you can take your pride and joy to!
American Fancy Rat and Mouse Association
Rat and Mouse Club of America
The Rat Fan Club