Where can you buy the 'One day Travel Package' for the dongzhimen bus?

Hi, it can be bought at the Dongzhimen Bus Station. I remember it leaves from Dongzhimen at 07:30 on Sat. Sun. and National Holidays and gets back at 15:30. As I know, it cannot be bought in advance, so you'd better go there to line up early to get a ticket!

As a second choice, the latest news in Apr. 2014 tells that there is direct tourism bus from Wangjingxi Metro Station (exit C of subway line 15 and exit D of subway line 13) to JSL every day now. It leaves the metro station at 08:00! Also you are advised to get there early to queue up for a ticket!