Steve Hoefer has written a great little how-to for building a $30 softbox for photo and video. While I tend to favor reflector-oriented lighting techniques, the ‘overwhelming softbox’ method (my term) that Steve outlines here is very useful for quick documentation photos or when you have limited space.

There are plenty of DIY softbox how-tos out there, but this one is exceptionally clear and well-written (like all his stuff), so you should definitely give it a look!