For an additional fee, there is also a fancy souvenir certificate available marking the day and time that you ascended the Tiananmen Rostrum. It can be personalized with up to 4 Chinese characters or 16 English letters. It's really nice and comes with a booklet of beautiful photographs highlighting military processions during previous anniversaries.
The reason there is a strict 4 character limit for Chinese characters is because most Chinese names are comprised of 3 characters. This is a greedy tactic designed to prevent 2 people (you and your girlfriend/spouse/grandmother/concubine) from having both names on one certificate.
However if you look like a foreigner and pretend not to know much Mandarin, it is possible to trick the clerk by requesting the Chinese translation of your foreign name. This will enable you to have six Chinese characters, which of course is you and your Chinese girlfriend but the clerk will actually believe you are German or Croatian and make a special linguistic exception if you approach the kiosk alone and smile while asking. It worked for me, and I'm neither German or Croatian!

