Tradition has always held that the flag unfurled that day is the one shown above, known as the Easton Flag. However, there is no documentation of this. The existing flag, somewhat tattered, can be traced back to a flag presented to Capt. Abraham Horn's company of the City Guard prior to their departure to the War of 1812. It was later presented to the Easton Library Company, and is still displayed there in a protective glass case. But the fact that this particular specimen of the flag dates only to 1812 does not mean the design was not Revolution-era. It's just that there is no proof one way or another.
In any case, today (well, technically yesterday, since it is now after midnight) was the big celebration, with Revolutionary re-enactors, a reading of the Declaration, rock and bluegrass performances, a re-enactment of the Delaware Indian treaty, clowns, magicians, and jugglers, and a big fireworks display on the river. Pretty loud, too, and I'm way up on the cliffs.
This is from last year: