DW-world.de just did a story on Germany's biggest hostel:
Germany's biggest youth hostel is situated in Cologne. It is a gigantic building: seven floors high and equipped with 500 beds, it served over 130,000 travelers last year. On any single day, as many as several hundred guests come through its doors in the form of individual backpackers, school visits or tourist groups.
"In the evening, there are, as a rule, between 350 and 400 people sitting down for food," he said. "Lunchtime is a little less busy because the groups are normally on the move then. However, there are still between 100 and 150 meals to prepare."
The youth hostel's Web site is located here.