Meet George Jetson! His boy, Elroy! Daughter Judy! Jane, his wife! Yes, the comedy of the twenty-first century is now described here on this page! (Gee, it's the twenty-first century now, and nobody's living in apartments that can raise over the clouds. I'm disappointed.) Let's start with the basics, they're probably most important. Who lives in this futuristic world? Well, there's...

George Jetson : The head of the Jetson family. He's rather clumbsy, and has trouble coping with his problems. It doesn't help that he has the most hotheaded boss in the area, Mr. Spacely. But it does help that he has a loving family, who is always ready to support him in his struggle with the often bizarre problems that he faces. He is always concerned about their well-being, and will often go to great lengths to take care of messy situations. And who else is in the family?
Jane Jetson : George's wife, who tries to keep the house under control, and get everyone to work / school on time. (With George, she usually fails.) However, for the most part, she is able to coordinate everything in the household rather well.
Judy Jetson : The teenage Jetson daughter, who basically embodies many stereotypes about teenage girls. Frightening. She's boy crazy (switching boyfriends at a head-spinning rate) and often gabbing on the phone. However, even though you wouldn't always get this impression, Judy is a kind person who takes the time to help others in need. In a movie, she even helped to save the future of music. Kind of strange, but hey, I'm not a storywriter for Hanna-Barbera, am I?
Elroy Jetson : The son of the Jetson family, always wearing green overalls and a matching cap. Elroy is intelligent, and likes to experiment. This usually results in explosions and general disorder. Elroy is very energetic and curious, looking into something whenever the chance presents itself. His skills have helped out his family numerous times, and he's always stumbling onto some..... situation.
Astro Jetson : The large grey dog who can speak English, and the Jetson's family pet. He followed Elroy home from school one day ("He's just a puppy," says Elroy), and manages to charm his way into the household. From there, he's a whirlwind, causing much stress for George (to whom he is very loyal). Astro often catches on to trouble before the rest of the Jetsons, which is very helpful, considering how often they meet some calamity.
Rosie the robot : She's a robot maid that the Jetsons were able to buy. I assume in the future, they've found a way to create bioroids, because Rosie has a rollicking personality. She is very sassy and often has some quip to fire at anyone she talks to. However, her service and dedication to the Jetsons is amazing, and she can help the entire family with their worries when they need it. Her main problem is how prone she is to encounter mechanical trouble!
Orbitty : A strange alien creature that Elroy found on a field trip to an asteroid. Actually, he found Orbitty's egg. After some mishaps, Orbitty became a normal part of the Jetson household. He has springy legs, and the habit of changing color to correspond to his mood. He can take just about anything apart.... and most of the time, put it back together!
Grandpa Jetson : Darn, I forget his name. Anyhow, despite his age, Grandpa Jetson is very energetic. (He can wear ASTRO out!) He has only appeared in around three different episodes. Life is certainly exciting with him around, though...
Henry : The superintendent of the Skypad apartments (where the Jetsons live). Aside from keeping the building together, he also does his own lot of inventing. One of his greatest achievements is Mac (we'll get to him next). Henry often helps out the Jetsons when they need it, and sometimes they need that help keeping Rosie maintained (which Henry seems to be able to do well)!
Mac : He is a robot created by Henry. He looks a little disjointed, and is made out of various parts, including a file cabinet. Mac was supposed to do the maintenance around the Skypad apartments at first, but then he fell in love with Rosie. (!?! Wow! Who'd of thought?) After making arrangements, they were allowed to see each other on a regular basis, and both found themselves able to resume their jobs again.
Di-Di : Maybe I should've mentioned her / it already. Di-Di is Judy's personal diary who we get the chance to see from time to time. It is shaped like a mouth, with an antenna sticking from the top, and it hovers around everywhere. It records all of the events of Judy's day, but not without making sarcastic comments!
Mr. Cosmo Spacely : George's tyrannical employer, who is always looking for excuses to fire him. Mr. Spacely DOES have a heart, but he only shows it when he's deeply moved. Mr. Spacely wants his business, Spacely's Sprockets (AAARRRGGGH! What IS a sprocket?!) to be the best out there, and is always pushing his workers. He is sometimes the cause of the Jetsons' problems. Fortunately, sometimes he is part of the solution too.
Mrs. Spacely : I forget her name too. Argh. Well, she henpecks Mr. Spacely occasionally (and not without good cause, since he devotes so much attention to his business). However, she's usually understanding to the Jetsons. Well, some times, anyway.
Rudy : The computer that George uses to do his work at Spacely's Sprockets. Rudy cooperates very smoothly with George so that he can get his work done. He's even helped George a few times to overcome his difficulties. Rudy gets overworked by Mr. Spacely's demands from time to time, so during those periods, he can be a little out of it.
Uniblab : A backstabbing freak robot who is supposed to hold a high position at Spacely's Sprockets. He has a big head. And he likes to gamble a lot. We don't see too much of him, but he has tried to get George in trouble a couple of times by making him look bad. (Basically by getting George to share his feelings about Spacely, and then playing them back in front of the boss. That was in the first episode.) Henry helped George take care of him whenever he started his schemes, though. Uniblab doesn't hold so high a position in the company now, but still does assistant work around the building.
Mr. Cogswell : He owns Cogswell's Cogs, a competitor of Spacely's Sprockets. He is very ruthless, and will do anything to one-up Spacely. He's not even above twisting the law to succeed. He will always try to take advantage of a situation and steal ideas off of Spacely, and sometimes this is at George's expense.
K-9 : A large guard dog robot that takes care of security at Cogswell's Cogs. He is very vicious, and will eliminate anyone who tries to meddle in his boss's affairs. There are ways to get by him, but you have to have a really good trick to do so.

Those are some of the main characters. I'll add an episode list on some other update... but not this time. Hope you can tide yourself over with this for now!
My Hanna-Barbera list is missing a sprocket.... I'd better go buy a new one.