1978! My first game in a magazine (Dragon #10). I persuaded Tim Kask (then editor of the Dragon Magazine) to buy me a drawing table as payment. He reniged, thank goodness, and I got money instead. The game was a parody of role playing games. If you ever cut out and tried it, you would discover it quickly bogs down in record keeping and takes forever to play.
However, Smashing has been revised and my new version is now very playable. Steve Jackson Games have, at long last, reissued (and changed my design somewhat... but I hear it's still good) SNITS.