Tabbycat is a video server prototype demonstrating the benefits of a proactive approach for distributing popular videos on demand to a large customer base. Rather than reacting to individual customer requests, Tabbycat broadcasts the contents of the most popular videos according to a fixed schedule. As a result, the number of customers watching a given video does not affect the cost of distributing it. We found that one workstation with a single ATA disk drive and a Fast Ethernet interface could distribute three two-hour videos while achieving a maximum customer waiting time of less than four minutes.