Since I’m continually running the latest betas or versions of software and add-ins – every once in a while my system will get in a wonky state.  I was having the issue where PowerPivot and PowerView weren’t showing up in my Excel 2013 ribbon and noticed a couple of others were having the same issue – If you’ve run into this problem, take a look at the Excel Support Team blog post - Excel 2013 PowerPivot or PowerView add-ins are not available and then follow the directions on updating your registry and you’ll be back in PowerBI heaven using PowerPivot and PowerView.