RSS 2.0Materials
In Alternativa 5.x, every face is drawn in its own display object, an instance of undocumented Skin class. Not that there's much to document any way, Skin simply extends flash Sprite class. Neverless this knowledge gives us some power to implement placeholders for things that you would have to wait for months otherwise.
One such example would be sprites. Would you like to insert any display object into your scene? Well, you can either implement custom material for that, or moan and wait for 5.1 (now 6.0)... and, you see, I hate waiting :) I'm sure you could do some good stuff with this, here are source files to get you started.
Another example would be object visibility control. IMHO, it is ridiculous to wait for 6.0 and remove objects from stage or materials from objects in the meantime, so I made a material for that too.