With gamers expected to rush out en mass to buy Modern Warfare 2 this week, retailers may be just as excited for the release as even the biggest COD franchise fans.

Solitaire may be as sticky as World of Warcraft. While users of casual electronic games (card games, puzzles, etc.) spend less time per session playing them than those playing non-casual games (role playing games, shooter games, etc.) they are just as likely to return to them months later.