First Saturday of the month. 9 am at the Shops at Gainey Village located on the southeast corner of Scottsdale & Doubletree Ranch Rd. But I have not been there.
Sponsored by Scottsdale Exotic Car Club:
http://www.scottsdaleexoticcarclub.com/
I don't know how active the club is in the summer. I haven't heard of anything recently.
AZ Bob