Tight spot

I’m in a tight spot, I need to make a quick gallery for a friend. It’s going to display thumbnails which, when clicked, display an mpeg video. Is there some simple PHP script(my host supports PHP) that I can use, so when the user clicks on a thumbnail, the video loads without reloading the entire page? Or would I be better off just making 15 pages(there are 15 videos in total) and just linking them all together to look like its being handled by thumbnails? I have to get this done by Friday… ANY advice would be greatly welcome. I’m great with CSS, so I can build the page very quickly, but my PHP knowledge is zero.