User can observe (establish a peer connection without providing any media streams).

Status bar. Also could not resist dragging jQuery in.

User can choose to use audio/video or both. Also visually mark pressed button.

Move styles to main.css and use kube.

Sort of works. This is as fragile as it sounds actually, because it works only in perfect cases. Ice candidates from Chrome produce errors in Firefox; also Firefox cannot create answer to Chrome's offer; sound is missing in Firefox(?).