Old games, files to download, at siteaboutnothing.
New levels to the fun little game Chip's Challenge.
Classic gaming at Gamespy.
More old games - looks like you can download several of Sierra Online's Quest-games here.
At Alex-soft.net they call it abandonware. Warning - that's an obnoxious site!
Games nostalgia - nice title. And they have a game called Jill of the jungle - almost worth looking at just for the title.