You can easily find many summer camps for kids by search keywords on google in English or Baidu.com in Chinese. Many summer camps are with a special theme, leadership development, English study, science, table tennis, ice skating, etc. Most summer camps in China are 5-day long and cost 2000-4000 RMB including 4 nights of accommodation.

If they're fat, you can send 'em here (see link)

I help in the summers at the Chinese Communist Youth League.  Don't  let the name fool you.  It've non political and very much like boy scout extreme camps.

there is an education business here in shanghai that offer summer camps, where they get to stay in cabins, go swimming and do many out door activities. They are generally staffed with foreign and chinese teacher. The place is call SiHui... they actually got the idea from a friend and I. We told them they should have a summer camp that doesn't mean more school but fun outdoor activities