Bittorrent isn't sequential by design, but you can tweak a torrent client to ask for pieces in order (e.g., Pando, using a bittorrent-like protocol, can do this

Bittorrent isn't sequential by design, but you can tweak a torrent client to ask for pieces in order (e.g., Pando, using a bittorrent-like protocol, can do this) -- though if you have a moving target in terms of the set of blocks you are interested in things a get a little more complicated -- a streaming-specific p2p protocol would likely perform better (see comments on this thread for examples).