Hey, Looks like an Exhibition right? Sorry you are wrong, in fact it's the birthday party of a 15-year boy Wang Chuibo who live in Nanning capital of Guangxi province, China.
The Shanghai-Expo-like Birthday Party was hold on the 17th August 2009 and spreaded rapidly during the Chinese netizens.
The yellow characters on the red arc means "Let's celebrate the 15th birthday of Wang Ya's first son - Wang Chuibo". Balloons are from other companies which attended the birthday of that boy, and you can tell who they are directly by reading the characters on the scroll hung under the balloons.
The yellow characters on the nearest scroll say "Fujian fellow association in Guangxi Province ......"
The yellow Chinese characters say "The subbranch of Stepwolf in Guangxin province ......"
"Nanning Henghao Decoration engineering Co, Ltd......."