Digger is a classic IBM PC game from 1983 made by Windmill Software. You can play it online via HTML5, online via Java or download a version for platforms both common and obscure. More ports are on the Links page. [more inside]
Fancy a $25 PC XT clone? With full Hercules graphics compatibility, peripheral support, and able to run MS-DOS and Windows 3.0? All you need is a Raspberry Pi, a C compiler, and 8086tiny, the world's smallest full PC emulator. Clocking in at around 25k of source code, this marvel of modern science is yours to do with as you will. But wait, there's more - you get the full BIOS code _and_ binary thrown in! (Also runs on just about anything 32-bit, if you don't fancy a Pi). If that's too big for comfort, a 4043 byte Obfuscated C version, winner of the 2013 ioccc championship, is also available.
Got a few hours to kill and want to spend a little time in gaming history? Don't have anything else to do until 2013? Check out Anacreon: Reconstruction 4021 (wiki) (previously), one of the earliest 4X games ever made, dating to 1987-88. The original version was DOS-based, but the creator, George Moromisato, released a Windows version in 2004 which has significant updates. [more inside]
The CRPG Addict is playing every PC role-playing came in chronological order. Currently, he's playing Ultima V. [more inside]