I created a video gallery recently in which the main feature was a dynamic overlay player. The idea being that when you are on a page with a grid of videos you could click on a video and just have it play on the same page in an overlay mask. When a video is selected the embed frame is loaded dynamically using jQuery.
There is an example of this on the video gallery page I recently created for EditExtreme.
So at any point during or at the end of playback you could close the overlay and the video would be unloaded and you would see the page exactly the way it was before you clicked the video. You can set the autoplay parameter of the embed so that the video will play immediately upon loading but it is important to remember that autoplay is disabled on most mobile devices to protect users against the data charges that could result from automatically streamed videos.
This gallery also allows you to use a custom placeholder / thumbnail for each video so you are not limited to only the options provided by your video service, such as YouTube or Vimeo.
This gallery is also fully responsive.