1. Pass you a note
  2. Meet you in our favorite Dungeons & Dragons dial-up BBS
  3. Write you a letter
  4. Visit your house
  5. Call you on the phone
  6. Send you a package
  7. Meet you out somewhere
  8. Send you a fax
    If you were work-related
  9. Shout to you from across the street
  10. Visit your office
  11. Talk to you over the fence between our houses
  12. Work late together.
    Suggested by @gwcoffey
  13. Use the can-string-can system we built from our adjoining backyard forts.
    Suggested by @donnie