Airberlin has a topbonus promotion for 300 miles per hotel review that are left on HolidayCheck.com website in September 2013.
You can leave reviews for stays that are within 24 months. HolidayCheck also offers Miles&More and AirBaltic miles for hotel reviews. You can access the website for this offer here.
This could be a good way to top up your topbonus account for an award redemption.