I looked. I didn't see any strawberry milkshake day. Vanilla chocolate and a coffee flavored. However, August 1 is apparently generic milkshake day, so I don't see any reason why you can't just declare it whatever you want to.

Also, I guess it's ice cream month all of July, so maybe your local ice cream shop will keep up the deals and promotions for the next two weeks.

I'm afraid I've been woefully lacking in ice cream eating myself. Need to pick up the pace. :)