Recent theoretical and simulation-based studies have confirmed the tremendous benefit of peer-to-peer (P2P) communication at reducing the cost of running a VoD service. To date, very limited effort has been paid to validate the concept of peer-assisted VoD service, especially in terms of system implementation and service deployment. In this paper, we present the case study of a peer-assisted videoon-demand (VoD) system. We designed and developed BitTube, a BitTorrent-compliant VoD system. By combining client/server and P2P downloading, it supports seamless transition across the spectrum from pure client-server mode to BitTorrent mode. Within this framework, we experiment with a series of piece picking policies to enhance BitTube’s support to video streaming and promote locality-aware P2P downloading. We evaluate our system over PlanetLab, which hosts the user-side component of the BitTube system and emulates the global-scale user requests to the VoD service.