Qingming Jie or Tomb Sweeping Day in China

Today is Tomb Sweeping Day (清明节)  in China . In Beijing, the Badaling freeway was clogged with people heading outside the city to honour their dead ancestors.
This blog had a very interesting post and excellent photos.

(AP photo)

Here's some more about it from Wikipedia:

The Qingming Festival (simplified Chinese: 清明节; traditional Chinese: 清明節; pinyin: Qīngmíng Jié). Pure Brightness Festival or Clear Bright Festival, Ancestors Day or Tomb Sweeping Day is a traditional Chinese festival on the 104th day after the winter solstice (or the 15th day from the Spring Equinox), usually occurring around April 5 of the Gregorian calendar (see Chinese calendar). Astronomically it is also a solar term (See Qingming). The Qingming festival falls on the first day of the fifth solar term, named Qingming. Its name denotes a time for people to go outside and enjoy the greenery of springtime (踏青 Tàqīng, "treading on the greenery") and tend to the graves of departed ones.
Qingming has been regularly observed as a statutory public holiday in Taiwan and in the Chinese jurisdictions of Hong Kong and Macau. Its observance was reinstated as a nation wide public holiday in mainland China in 2008.
Qingming Festival is when Chinese people visit the graves or burial grounds of their ancestors. Traditionally, people brought a whole rooster with them to the graves visited but the occasion has become less formal over time. The festival originated from Hanshi Day (寒食节, literally, Day with cold food only), a memorial day for Jie Zitui (介子推). Jie Zitui died in 636 BC in the Spring and Autumn Period. He was one of many followers of Duke Wen of Jin before he became a duke. Once, during Wen's 19 years of exile, they had no food and Jie prepared some meat soup for Wen. Wen enjoyed it a lot and wondered where Jie had obtained the soup. It turned out Jie had cut a piece of meat from his own thigh to make the soup. Wen was so moved he promised to reward him one day. However, Jie was not the type of person who sought rewards. Instead, he just wanted to help Wen to return to Jin to become king. Once Wen became duke, Jie resigned and stayed away from him. Duke Wen rewarded the people who helped him in the decades, but for some reason he forgot to reward Jie, who by then had moved into the forest with his mother. Duke Wen went to the forest, but could not find Jie. Heeding suggestions from his officials, Duke Wen ordered men to set the forest on fire to force out Jie. However, Jie died in the fire. Feeling remorseful, Duke Wen ordered three days without fire to honour Jie's memory. The county where Jie died is still called Jiexiu (介休, literally "the place Jie rests forever").

For more information on the history of Qingming Jie, see this and this  . To honour dead ancestors, some people even buy them paper iPads.