I dunno if these are illegal or not, they're so old. I found this site a while ago, it has basically every old sierra game, all the Police Quests, Quest for Glory, Space Quest, Leisure Suit Larry, and all those other great old "quest" games. I downloaded pretty much all of them and was entertained for months, reunited with those games I played as a kid.
http://hyd.org/abandonware/sierra/