Internet Archive offers nearly 2,400 MS-DOS games for free. Select the desired game and click the "Click to Begin" button to play directly in your Internet browser. (Select titles can be downloaded as well.) Choose from titles such as Bruce Lee, Stunts, Deluxe Ski Jump, Lemmings 2: The Tribes, Total Carnage (pictured), and many, many more. (So much for being productive in 2015.)