DSx86 is a PC/DOS emulator for Nintendo DS written by Patrick Aalto. It’s purpose is to allow you to run old DOS games on your Nintendo DS game console. Some of the older games run quite good and bring back memories.

Release notes:

Sverx has continued improving my Smooth Scaling algorithms. This version has faster smooth scaling in all the 640-pixel wide EGA and VGA 16-color modes (640×200, 640×350, 640×400 and 640×480). The 640×480 mode is now fast enought to be used also on DS Lite (it used to be a DSi-exclusive feature), though the screen refresh will be limited to 15fps. Big thanks to Sverx for his hard work on the smooth scaling algorithms!

http://dsx86.patrickaalto.com/