Petaluma; Gnoss; Aubenas, France; Healdsburg; Shawnee Field; Cloverdale; Sonoma Skypark; Ukiah; Sea Ranch; Nut Tree; Napa; Carson City; Mindon; Santa Rosa; Concord PIC, bunch of others dual.
I took a lesson in a helicopter, with my CFI neice no less (it runs in the family). There are many parallels with trike flying, in some ways more than with fixed wing aircraft. It in other ways it is of course completely unique.