One Tick / Pulse Pressure Plate
While building an adventure map, I needed a way to give items in a chest using hoppers when players walked across a pressure plate. The problem was pressure plates stayed on for too long and the circuit would end up giving the player multiple items. I looked at various options such as pulse shortners etc. But they either had too many components or weren't very flexible with regard to placing the input (pressure plate) and the output (hopper).
After a bit of playing around, I came up with a compact design that can be placed in pretty much any orientation you need. Add a little redstone wire if you need your pressure plate further away.
The above isn't inverted, so the output is normally off. When you hit the pressure plate the output redstone torch flashes for one pulse. This might be useful for a dropper or dispenser.
This one adds another block and redstone torch to invert the output so it's always on. This is more useful for triggering a hopper, which is what I was needing.
Here's how you would run redstone wire to put the pressure plate further away.