Utility to allow for running DVD-requiring apps / games from the disk?

[spaceballl]

Just got my younger brother Roller Coaster Tycoon III for Christmas (tiz an old one, but a great one!)

We're not big fans of physical media around here. I think I read someplace that there's a utility that will copy games' DVDs to the hard drive, and allow the game to run completely from disk. Anyone know of an app that does this?

Thanks!