Django is a web development framework for Python. I used it for a few web sites, including a relatively large one. I must say, my overall impression is rather ambivalent.
First of all, Django is definitely excels when you need stuff done, quickly. A lot of stuff simply works out of the box or with minimum effort, including DB access and ORM, caching, templating and so on. And there are so many extensions available! Probably only some PHP frameworks have more plugins and extensions, but who wants to write in PHP for a living?