Sometimes you'll find yourself in the middle of one although I'll try to stay out of their way. I like to shadow the racers from outside their course to see how we stack up for speed.
If I'm somewhere near a known one like the Eggemoggin Reach Regatta, we'll hang out and sail nearby for a while to watch. It's always fun, especially if you're near the windward mark and they'll be popping spinnakers.
Out in the islands of Penobscot Bay, there are some weekend fleets we'll watch as we sail through. Many are ancient one design boats indigenous to the communities. Always fun. How can you not watch a sailboat race like that?