Excellent news for anyone "working" from home on today's snow day. The Internet Archive has brought online free, browser-playable versions of classic MS-DOS games.
The Oregon Trail is an obvious candidate for whiling your day away.
I'm also a big fan of Koei's war simulation games like L'Empereur and Romance of the Three Kingdoms. And who can forget Kings Quest IV: The Perils of Rosella or the original Sim City?