Hyper-V Program Manager
The one, the only, the infamous DOOM. I distinctly remember when this game first came out (1993). It took me 6 days to download it from my local BBS (it was in a 6 part archive and I could only download one part a day before I exceeded my daily time limit) and when I finally got it up and running I was *scared*. I do not think any game has had the initial impact on me that DOOM did.
DOOM had many firsts for a 3D shooting game. It had different leveled floors, non-perpendicular walls and a myriad of other new features. My personal favorite feature would be the fact that if one of the monsters in the game accidentally gets hit by 'friendly fire' from another monster - it will turn and attack the offender, and they will fight until one of them is dead (this is very handy at times).
Unsurprisingly, DOOM runs quite well under Virtual PC. The reason why I say 'unsurprisingly' is because DOOM is one of the standard programs we use to 'bring up' a virtual machine. Which is to say, whenever we make a major architectural change - one of the first things we do is check if DOOM still works.
You can read more about DOOM here: http://doom.wikia.com/wiki/Doom