Since there are ‘Muttertag’ and ‘Vatertag’ comnig in Germany, Lufthansa is giving away 20€ voucher codes here.
The basic T&Cs are:
- Only for flights departing from Germany
- Book between 2016-04-23 and 2016-07-23
- Travel between 2016-04-32 and 2016-10-23
- Limited to 1 code per mail address
If you get an error stating “no more vouchers available” try again the following day. It seems as if there is a daily limit.