Racing tracks and harness racing can be found throughout the state, and the calendar of races is available online.
At NHF there is news footage of these activities that spans many decades, and some of it is now being digitized with the support of an NEH grant. Here are two clips already, one from Bangor and another from Skowhegan.
https://collection.oldfilm.org/Detail/occurrences/20352
https://collection.oldfilm.org/Detail/occurrences/3536
Here is a clip of the statehouse debate about betting — unusually silent for about 30 seconds — and another about John R. Braden Night that was recollected 50 years ago.