Yeah, I need to create a four-box (of equal sizes) split-screen in a scene of my movie pretty much showing a character in each box doing a different activity. How would I go about doing this split-screen?
Track motion is, I think, what you might be looking for. With four video tracks (and probably only one active audio track), track motion will allow you to set the screen size (divide each dimension by two) and pixel address of the center. Applied to all four tracks with the center address set appropriately, you'll get what you want.
I highly recommend Tsunami. Sure the effect is easy enough to do, but Tsunami will do it VERY fast and save you time. Other tools on it are valuable as well.