If you take an sticky piston and face it upward, then place a redstone block on it's face and taking out a redstone wire out of the redstone block, the piston is stuck in extracted position untill redstone block is destroyed.
Steps to reproduce:
1. Open any world.
2. Place sticky piston facing up.
3. Place redstone block on face of the piston
4. Place any block near piston and place redstone dust on top, so it touches the redstone block.