An event that stops emitters from going through bricks like with a fire it goes through the ceiling sometimes that this event would block it from going any farther then that brick/plate/baseplate.
an event with a certain player lets say frank wants to have a way that to of his friends billy and bob can go through a door but anyone other than them can't go through (only one example of many other things you can do with it).
you can make a way that you can X-ray for Hidden "Bricks" for example you can stand in one area and see where mines are but once you step of you can't see them anymore.
These would be kool events (I spelled cool wrong on purpose so don't attack that error in spelling)
What are your ideas?