The MapTime server is down again. Sorry! (Hopefully it will be fixed shortly.) In the meantime, why not check out the OneZoom Tree of Life Explorer, which seems to be a nice tool for exploring evolution. It includes a time-based animation of the mammalian and amphibian trees. (More taxa will be added.)
The good news is that when the website is backup, it should have some new features including a second TimeLine. More on this soon. In the meantime, please get in touch if you have any questions or would like more information.