VideoLAN is a DRM-free video player for Windows, Mac and Linux OSs, capable of DVD playback and streaming video. It even lets you skip over those annoying ads at the beginning of DVDs.
Miro is a DRM-free platform for watching streaming internet video. They write: "We're developing the Miro internet TV platform so that watching internet video channels will be as easy as watching TV and broadcasting a channel will be open to everyone. Unlike traditional TV, everyone will have a voice." This project was formerly known as Democracy TV.