I have implemented some animated transitions for my interactive skymap, enabling a smooth change of the selected projection. Here are some videos showing the effect. The first one goes from Hammer-projection to Equirectangular, Craster Parabolic, Eckert II, Focaut and finally back to Hammer.
The second video shows off some of the weirder projections possible with d3.js. Starting with the not-so-weird Aitoff via Bonne, Collignon, Ginzburg IX, Hill Eucyclic, L'Arrivée back to Aitoff.
Check out the open-source GitHub repository at https://github.com/ofrohn/d3-celestial.