Turns out a lot of PowerPoint folks don’t know this — which has become one of my favorite Windows 7 tricks!
Open two PowerPoint presentations.
Press the Windows key and the left arrow key on your keyboard.
The active window will resize itself to take up the left half of your monitor.
Select the other presentation.
Press the Windows key and the right arrow key on your keyboard.
Presto! Both windows are side-by-side.
This trick works with whatever window / application is active, not just PowerPoint.
I find it faster than dragging the window off the edge of the screen (which results in the same half-screen size and position). Thing is, if you have two monitors (like I do), dragging takes both monitors into account so you end up with half a screen on the left monitor and half a screen on the right — which is never what I want. This trick works with whatever monitor your active windows are on. That means you can actually open 4 presentations across your two monitors for quadruple the fun!