The studio itself was founded following the strike of Disney in 1941. A group of individuals, headed by John Hubley, decided they no longer wanted to do the ultra-realistic style of animation. They wanted a more stylized film by experimenting with character design and perspective. After a few early films the studio was contracted by the US for a series of animations for the government.
Here are two videos of Gerald McBoing-Boing and Mr. Magoo:
The UPA studio scored many hits in their stylistic portrayal of content. The studio even sought to adapt such content as Edgar Allan Poe's The Tell Tale Heart. UPA slowed in steam toward the end of the 1960s with the firing of animator's such as John Hubley. However even today they are considered as one of the top animation studios to have existed.
For me the most interesting part of UPA is the fact that they decided to walk away from Disney just to try new things with their art form. These people took animation to new heights and made people realize that animation did not always have to strictly imitate life. For me I have never considered any limitations when working in this field and I think that is in large part due to the UPA studio. It is so visually appealing with simple altered perspective backgrounds and diverse color schemes.
I would consider some of the work done by UPA as art that could be hung is museums as drawn pieces. More so even than Disney at times because the work is so stylized that it becomes its own artistic entity above the aspect of film. Their use of angles in their shots is so effective that each shot seems to tell its own story. The monochromatic backgrounds and very flat characters move around in worlds that are still completely believable despite the graphic look. It gives me inspiration to try new things in animation and not to limit myself to creating characters and worlds based on rules.
Below are some more stills of their work and a link to a site about them: