On Wikipedia you can read about the Berlin Wall.
You will find an interview with Sarah Jane Dickenson, author of the play Not Yet here, some background about the writing process here.
There is also an article about the play and one about the performance at the 20th anniversary of the fall of the Berlin Wall.
Here you can download the German script:
“Not Yet” – The German script
If you have trouble opening the file, you might have to install Adobe Reader.
If you want to print the scipt, use the option “4 pages on 1 page” of your printer!