Matroska is an open source video and audio container format, that is quite popular in the release scene. Unfortunately the PS3 is still not capable of playing an mkv packed stream (at least not with the original firmware), hence a remuxing is advised.
mkv2vob is a pretty small tool that repacks a Matroska file into video objects that are used by the DVD standard, enabling to playback the stream on a PS3 directly or via any media center software, like TVersity.
Alternatively you can also use PS3 media server. The Java based DNLA media streamer converts formats on the fly.
For Windows 7 user: deactivate your energy saving when running a stream.