ZOMG! okay so tripwires are getting added to minecraft (1.3) they can be crafted or found in jungle ruins where there are traps (spoiler alert) and there are dispensers with arrows in them. there is also emerald blocks but they are purely for storage not for building because they are so rare. also there is an adventure gamemode that doesnt allow you to break any blocks but does allow you to open chests, activate levers and buttons, and interact with testificates. leave a comment for any other questions you may have!