A 3-year study in Singapore has discovered that the average primary and secondary school student in Singapore plays 27 hours of MMO games every week - more than 1/7th of their time. MMO stands for Massively-Multiplayer Online and includes titles like Guild Wars and World of Warcraft.
Games like this can bring out addictive tendencies in people who have them, and have been linked to extreme behaviour in people of all ages. Playtime of just under 5 hours per day, every day, seems like quite an extreme amount, but perhaps Singapore kids get more free time than kids in the UK.
The government has taken what many would call an "enlightened" approach to the issue, recognising that regulating the games or the Web won't work and would just drive the behaviour underground or out of the country's jurisdiction. Instead, it recommends that parents and kids work together to rectify unhealthy behaviour.