- take a day trip to the great wall - very worthwhile!
- the forbidden city
- tienanmen square, rent a bike and ride around, there are museums on the square and you can have your picture taken as an emperor or empress
- Peking duck restaurant (delicious)
- the night market, outdoor food vendors where you can see all the amazing foods the Chinese eat
- Temple of Heaven and nearby park, where you can see many retired Chinese gathered to sing, knit, play dice, and socialize - great people watching
- the flea market where you can find Mao memorabilia and propaganda posters, among other things over 6 years ago
I agree with everything RoundTheBend suggested, but also want to add the Summer Palace and Olympic Stadium to that list!
The audio tour of Forbidden City is also pretty good.
Ho hui is a nice area for relaxing dinner & nightlife. Another good evening activity is to catch an acrobatic show. over 6 years ago
798 Art District, center of Beijing's contemporary art scene.
Beijing Museum of Contemporary Art. (not part of 798)
Wangfuxing St.--enormous shopping street with dancing-water fountain.
Of course, The Forbidden City and Tienanmen, Great Wall, Summer Palace, Ming Tombs.
Beihai Park is beautiful, with great views--near Forbidden City. You can watch people folk dance there.
Catch some Beijing Opera. about 6 years ago