I thought it was possible, but unlikely, that I had coined a new phrase in response to a conversation about garage sales. Alas, the term "garage sailing" has already been coined.
Still, regardless of who first used it – I think it's a much cooler alternative to telling someone you're "going to a garage sale" or "having a garage sale" (it can be used in both capacities).
Q: What are you doing today?
A: Oh, just… GARAGE SAILING!
The nautical tie-in opens up a world of possibilities. Except I wouldn't recommend resorting to piracy – unless the garage sale happens to be on international waters.