I know a language school that is hosting a bus to take a group of people to Sheshan National Forest Park to check out the sights, visit the observatory, learn Mandarin, and just get the hell out of Shanghai for a day.
The cost is currently ¥250/person. But if other people want to sign up soon the price can drop to ¥200/person! Because the bus would probably be cheaper if it's booked sooner.
The trip includes:
*Transportation to and from Sheshan National Forest Park *Admission to Astronomy Museum *2 hours of Mandarin lessons *Lunch *Soft drinks and snacks during the day *1 Free Drink at a bar in Jing'An, and discounts after that