Mousehunt

MouseHunt is a popular Facebook application in which players, referred to as hunters, catch mice with a variety of traps in order to earn experience points and virtual gold through passive game play. From time to time the developers add new locations and mice as well as sponsor periodic giveaways and tournaments. MouseHunt was developed by HitGrab, Inc. under the direction of Bryan Freeman and Joel Augé and released to a select group of participants for beta testing in early 2008. On 7 March 2008, MouseHunt was officially released to the general public. Just nine months later, MouseHunt earned its creators a $250,000 development grant from Facebook. Though MouseHunt was originally catered for the US population, specifically those who live in GMT-8 to GMT-4, MouseHunt is hugely popular in Singapore, especially with secondary and tertiary students.

On my opinion, MouseHunt is pretty fun. There are also a few 'cheat' sites such as http://furoma.com/ and http://mhwiki.hitgrab.com/wiki/index.php/Main_Page. It is suitable for all ages. Though it feels a bit boring in the beginning (What am I doing catching virtual mouse with a horn???), but you will normally get hooked into it once you reach the rank of a Journeyman. For those who are interested, get a Facebook account and go to http://apps.facebook.com/mousehunt/.

Source: Wikipedia