Windows only: uTorrent, the most popular BitTorrent client on the planet, has released a new 2.0 beta complete with bug fixes and new features, including UDP tracker support.
UD-wha? As all-things-BitTorrent weblog TorrentFreak explains, UDP trackers are much less resource intensive than HTTP trackers, and most torrent sites out their support UDP—meaning that if uTorrent, the most popular torrent client, were to support it, that's great news for all the torrent trackers out there. On the surface that might not seem like the most exciting news, but it will likely mean browsing your favourite torrent site in a browser could be significantly speedier now that your BitTorrent client isn't slowing down the tracker with all those HTTP requests. Hit up the uTorrent forum for a list of all the changes and fixes in the beta if you're ready to try it out.
uTorrent 2.0 Beta is freeware, Windows only.