TARcon was held after every season, until season 23. I don't know if one was held after season 24, as the site's home location online (the forums at televisionwithoutpity.com) was closed by Bravo a few months ago, and I've not seen anything about subsequent events.
Racers do have their own group, and have been known to plan events for the start or the end of various seasons. These are private events, and generally aren't open to others except by invite. CBS has in the past at least invited the final three teams to either New York or L.A. for the finale, and to appear on a CBS show for the check presentation to the winner, but again, that doesn't seem to be happening these days.
Something to keep in mind, while TPTB did organize a tenth anniversary event in 2011-12, that was unusual for them, as there are now approximately 500 living Racers! Even a Racer get together now becomes a major production.