DAX: Always get the Latest date for a slicer

You've done it. After some development, your Power Pivot model has some awesome-sauce, has a slicer for the day/month/year, and is ready to do some serious data insight. You set your slicer to the current moment in time, deploy it to a Power Pivot gallery in SharePoint, and start using your model. But then.tomorrow happens. And now your slicer is out of date. Every time a new day happens, the slicer gets farther and farther away. Your users don't want to click the latest date every time they want to use the model, you'd like to make it dynamic so that you don't have to click on the latest day every time. Rob Collie does an excellent introduction into this topic in his new book, and gives a good background on using a latest date slicer. I was recently reviewing this concept with a class when they went through all the different scenarios that this might apply in. (You know who you are! :)) I thought this would be a good opportunity for a blog post, to show the different levels and ways that this concept could be applied: