The Minecraft 1.4 Pretty Scary Update 2012 is due on the 24th of October. It brings new mobs, a new boss and new blocks. Blocks include Command Blocks and Beacons. There are sounds to go with the new mobs and new sounds for old ones. Some new commands for the game to use like setting the spawn point of yourself and others plus a few more. There’s new vegetables to grow like potatoes and carrots and you can use the combine the carrot with a stick and use it to direct pigs with saddles.
There’s a bunch more updates to the behavior of the mods and many more. Read the complete 1.4 changelog here or download the pre-release and try it for yourself now.