Sometimes, Simon loves a trick or a puzzle so much he writes it down several times over the course of a couple of days. he also really enjoys teaching this to everyone he can grab hold of.
Pythagoras Theorem Proofs
The old Gaussian trick
Squaring tricks
The kitchen drawer containing small objects like matches and tape is always a mess as Simon scavenges for treasures.
The above was inspired by Presh Talwalkar and his Mind Your Decisions. Brilliant is another source of ideas for crafty paper puzzles here:
Geeks out of the box 