The programmer who first put Solitaire onto PCs was once quoted as saying that he had singlehandedly reduced America's global competitiveness. We confess to liking Big Fish Games, which allows you to download games free for an hour's play. And most of the time, an hour is enough. There are hidden object games, "match 3" games, solitaire variations, mahjongg games, and more. Warning: all computer games may be addictive. In fact, the Chinese government interrupts online game players after three hours of play to tell them to "do suitable physical exercise" (reference). The nonprofit Online Gamers Anonymous might be the site you're really looking for.