Know any animation software names?

I love making little cartoons, and for the past few months, pivot and Stykz has worked really well. I even have a weekly series going, but that's beside the point. Lately, however, Stykz and pivot have both been having...technical difficulties. Also, I want to make a fun, aimated little movie, and pivot just isn't good for that. Is there any free, downloadable animation software that fits my...agenda?