It won't necessarily increase productivity, but if what you're doing that isn't pressing, passively watching a movie while you work can be relaxing. If you don't have a second monitor to do it on, here's how to put it on your desktop.
Some of you may already know about this feature in VLC, but it was new to us — if you go to VLC's preferences and hit the Video button, you'll have the option to choose the output type. Instead of default, switch it to DirectX video output. After restarting VLC, you'll notice that under Video in the toolbar, the "DirectX Wallpaper" option is now clickable.
Not surprisingly, selecting it overlays the video on your desktop so you can watch it full-screen, while you do work on top of it. While some of you may be able to minimise VLC entirely and still watch the movie, I found that that took away the video entirely — so I just resized the VLC window really small and stuck it in the corner of my screen. Surprisingly, too, it didn't bog down my system at all. Everything ran quite smoothly. Note, though, that you might need to re-apply your old desktop wallpaper when you're finished.
For you Mac users looking to do this, you can actually do so with QuickTime and the previously mentioned Secrets preference pane (or any of the other hidden preference tweakers out there). Just uncheck the option for Quicktime that exits full screen when switching Windows, and you'll be able to bring your dock, menu bar and other windows in front of the playing QuickTime movie. Again, it isn't the most productivity-enhancing tip, but it's sure to make your less important work (or really boring and tedious work) a little more fun.