Blocking Software

We want a software program that enables people to block certain websites and computer programs for a certain amount of [login to view URL] program is for students to help them concentrate on their study without any distractions from their computer (facebook, pokerstars, COD, youtube, etc.) The only way to remove the block should be by restarting the computer, the interface should be clean and simple, and we need two versions (a mac version and a windows version).