An annual event- Tubachristmas- bunch of people playing tubas, sousaphones, baritones and whatnot in Thanksgiving Square, in Dallas- Friday, December22 , concert starts at noon; rehearsals are earlier.
This is a national event. Look up other city locations at
www.tubachristmas.com.
The tuba players themselves have some visual interest, and then it's a good place just to photograph happy crowds in colorful clothes.
As best I can tell, DART is the best way to get there.
Photos attached from last year to give you an idea of what it's like.