May 19 is China Tourism Day across the country. This means hundreds if not thousands of cheap or free tourism activities organized in China, including many kids will love like the Water Cube in Beijing.
Free kids activities are plentiful in the US but hard to find in Beijing. But this also of course means massive crowds. But considering the rising costs of tourism sites in China, it can be a good chance to see things that you might otherwise not
Specific information is hard to find in English. Different provinces and cities are organizing their own promotions. Shanghai says 37 attractions will be half price. Spots in Tongchuan city will be free. Also Jiangjiajie World Heritage forest.
The China National Tourism Day was made an annual event in 2011, and always to be on May 19. This means when it falls on a weekend like in 2012 and 2013, the crowds are bound to be even bigger than the inaugural year when most people were working. Hopefully the details for foreigners will become more transparent as tourism day develops.