If you are bored just to explore the world of Minecraft, then I suggest you fight with a new powerful Dinnerbone boss, which is copied from one of the creators of Bukkit and after defeating him, the player will get a unique thing.
How to use Dinnerbone Boss
- Copy the command text from a file (Ctrl+A -> Ctrl+C)
- Launch the game and get a command block, to do this type in console /give @p command_block
- Put the command block on the ground
- Click on it right click and paste the command in the “Command console” (Ctrl+V)
- Activate the command block using the button or the lever