Video Player

This observation based solely on my own experience, but I rarely use volume slider on videos. Moreover, %80-90 of the time, I only use the play/pause button.

Imagine that UI disappears seconds after the video starts playing but you can still call up the controls by moving the pointer over the player (or tapping on it).

This design improves the viewing experience (and makes embedding simpler) by removing any additional control until requested by the user, yet gives an "advanced user" all the controls available in the original design.

As an additional advantage, this player could well be made touch-friendly without requiring a redesign.