There are lots of things I feel others ought to know (because after I knew them I felt I understood the world a lot better than before) but not many fall under procedural knowledge. Computer programming is one thing I really value having learned, mostly for non-procedural reasons (clarifies thinking, adds a large useful set of analogies etc.) which has also proved practically useful (e.g. writing scripts for repetitive things and understanding computer errors).

Another thing I've just recalled: If you run out of gas somewhere you can call a cab and ask the driver to bring a can of gas with him/her (this applies in Iceland at least, YMMV).