Animation software free?????

you know how there are animated shows, about 20 minutes long per episode, such as Family Guy, The Simpsons etc. Well, i have a great animation idea in mind, and i want to create a 10 minute animation, in color, but i dont want to have to draw every single frame on ms paint. i would use pivot stickfigure animator, but that only does stick figures, but do you know of any FREE software i can download that will make a 10 minute animation like pivot does where you choose where the knee is, elbow is, and you just adjust those a bunch and soon youll get a movie. it would be kind of like the animation of the simpsons, only people are skin colored, thankk you (remember FREE)