An ex-googler friend and I made a similar tool as a weekend project a while back http://www.snptz.com/ (code: https://github.com/tedpower/snptz)

We later ran across another implementation of snippets here: https://github.com/kushal/snippets

"at" is very handy for scheduling one-time scripts/commands

  echo my_script.py | at 4am tomorrow

then list queued jobs with

  atq

note: its not enabled by default on mac os x, see

  man atrun