If you aren't a pupil, a student, a child under 14 years old, or disabled (cause there are better reliefs in this cases), this deal could be interesting for you.

https://www.topticketline.de/tickets.aspx?shop=XMWKD10P

With this link you'll get a 10% X-mas rabate on all seats for the shows until May 2008. You have to book until 31th December 2007. If you click on this link the rabate is discounted already.