Realistically, I'll probably never need to use this information, but I've never been one to be imprisoned by realism.
  1. Shoving a hose down a toilet's u-bend will give me an unlimited supply of air
    Kingsmen: the Secret Service
  2. How to Hotwire a card
    Like, every movie/show. (Technically don't know how to, but I feel I need to learn ASAP. People always have to do this.)
  3. Putting axel grease on a bullet will help it go through reinforced doors.
    High Dive.
  4. Picking a lock
    Suggested by @sarblake