What monitors do you have (exact model numbers) and which one do you want to try calibrating? Generally you need the professional grade CRTs otherwise your options are pretty limited (such as the one suggested by DankEngihn). You will need Windows XP or higher for best results, with older OSes than that you either get a slightly lighter black level or crushed shadows. But a lot of games from pre-XP era actually look just fine with crushed shadows, if not, you can simply turn up brightness to light up the shadow areas but you will get a slightly lighter black level (which is okay if not playing in the dark). Also some games are absurdly dark (Deus Ex,..), some games will refuse color profiles (Half-Life 2,..) and some (especially older, pre-XP) games look better without color profiles.