For web designers, its always a constant struggle to get those flash, youtube, or vimeo videos tuck under divs where you need them. They somehow always behave like their z-index is close to infinity.
By default Flash content in a web page will appear on top of other elements on the page, including floating menus, inline popups etc. This can be pretty annoying if you have a flyout menu on your page and it goes behind the Flash video and this post shows how simple it is to fix. This works in all browsers inclding IE6+
