The latest Minecraft snapshot adds an animated texture system to the mix.
To gaze into the future, you might need to hire a seer. To see into the future of Minecraft, all you have to do is download the latest snapshot. While major patches come every few months, all the latest features and tweaks are field tested in weekly updates that interested parties can test drive. This week's release changed the way textures work, allowing for subtle animations to be added and enhancing the sense of rural immersion, or possibly inducing vomit if you do it wrong.
Within moments, modders seized ahold of these new features and quickly threw them from the cliff of logical extremes. Why make your pixel paradise look that much more vibrant when you can make the walls crawl? Thankfully, even the most dizzying animations cannot hold a torch to this vomit-inducing shader mod.
Equilibrium-disturbing abuses aside, the new features not only make Minecraft a more lively-looking place, but also improves how the game loads textures. Instead of loading from one large image file, Minecraft now can load textures from individual files, which opens up a host of opportunities. Beyond simple animation, this new system improves support for custom blocks. It can even mix and match resolutions, so if an update adds new blocks and items, it won't completely break your current custom texture pack.
While the latest snapshot can be downloaded here, it's recommended that you use a custom launcher (like Magic Launcher) to load them, so that you can revert back with ease. Remember: practice safe modding!