The latest chapter in the Mega Man X games released on the Playstation 2 earlier last year, but now there's a demo of it for the PC.
http://www.4gamer.net/news.php?url=/pat ... anx8.shtml
Click on the big red button at the bottom to download it (108 megs).
For the uninitiated, X8 is a traditional side-scroller implemented in a 3D environment. It stays very true to the old games while using the PS2 to push better special effects and graphics.
Interestingly, you can run it at 1600x1200, though the low-res nature of the PS2 texture work shows. Although it is a Japanese demo, it has full English subtitles and voices if you chose that option during the install.