The rumour mill is reporting that the Wachowski Brothers and Keanu Reeves have met up to discuss a new two-movie Matrix project. The new films would be in 3D and would probably feature bullet-time and further the thoroughly confused mythology of the second and third movies.
My enthusiasm for this news is sorely lacking. The first film was solid, the second was rather boring and the third fell flat but was livened up by the battle for Zion (just don't ask why the defending battlemechs didn't have any armour or protection for the pilots). A fourth and fifth instalment would seem to be totally superfluous, especially if it means they resurrect Neo and invalidate his sacrifice from the end of the third film. Still, this is just a rumour so far.