When we were there a couple of weeks ago, I asked to try a sample of the Avocado Margarita at La Cava and they let me! Since it's frozen and made in a blender they seemed to have some left over. The people next to me heard me ask and asked to try and they had samples too. They put them in the shot glasses and acted like it was a totally normal request. Since the avocado one is so popular, I think the chances are good that there would be some extra newly made that you could try. I didn't think I'd like it because I'm not a fan of Midori, but it was really good! My first choice was the Jalapeño Margarita which might have been the best margarita I've ever had! Definately stop by La Cava if you are a margarita fan!
In addition, I have to highly recommend the margarita flight at the Hollywood Brown Derby/Brown Derby Lounge at DHS. Traditional, mango and pomegranate all on the rocks with a salt or sugar rim. So good!!!