Comment For DOS games. (Score 4, Insightful) 367
Well, for DOS games, DOSbox can do a number of different scaling modes. From the Wiki:
normal: nearest-neighbour scaling (big square pixels)
scan: like normal, but with horizontal black lines
tv: like scan, but with darker versions of data instead of black lines
advmame: smooths corners and removes jaggies from diagonal lines
advinterp: identical to advmame
rgb: simulates the phosphors on a dot trio CRT
As for old windows games, I hope to hear something else.
One last note, Myst was re-released as a "Masterpiece Edition" with higher resolution re-rendered graphics.