Just remembered something that might be of interest. When i was in Phnom Penh i joined the local Hash Harriers on their Sunday run and really enjoyed it. Anybody can join, just meet at the train station at 2.45 on a Sunday, you will be picked up and taken by truck to outside (maybe not always outside) the city, then you will run (or walking course for the unfit) following arrows and other directions that are painted on trees or the ground. Half way through the truck will be there with a huge cooler packed with ice cold beer, drink as much as you like. continue the race and the truck will be waiting at the end of the circuit, drink as much as you like until they drop you off at the station. This is a great way to meet ex-pats living there and locals too. We ran through a couple of villages that day. Cost was $5, and $2 for locals. 8-10 kms is the usual distance. At the end of the day some locals and ex-pats may invite you to join them at a restaurant.
I do not know if it is counted as a type of sport activity or not but this is a common sporty activity of Cambodians which i felt ! I also saw some boys playing football but i do not think so that its very famous out there.