0 seconds. Search the forums for "copyright" and other related words. This issue has been battled over and over again, but the general consesus is--if you didn't pay for it, you can't use it. For any amount of time. Some people say do it, you probably won't get caught, or you'll get a Cease and Desist order before you're sued, but I say don't do it. It's not worth it, and it's not legal.