I believe they actually run all night. I know on my last visit - they were operating late in the evening. In addition, they have set rates for various hours which include the hours between 7 PM and 8 AM. Here are the prices as of June 2006: a ride of 40 minutes up to 6 people € 80,00 a ride of 20 minutes after the first 40 minutes € 40,00 night time personalised and standard tour (from 7 p.m. to 8 a.m.) 40 minutes maximum 6 people € 100,00 night time ride of 20 minutes after the first 40 minutes € 50,00.