COOKIE!!
Okay, so I'm not the famous blue puppet, but get me near Dave & Andy's and I turn into the proverbial cookie monster faster than I'd like to admit. Their Cookie Dough ice cream is so packed with cookie dough that I've been tempted to bake it.
Just in case that wasn't enough, though, they also offer waffle cones that are made in-house, with an M&M treat hidden in the bottom. If you're in oakland and need to cool down, you can't do better than Dave & Andy's for a great ice cream snack.