This free Excel report shows the most popular times of day, by day of week, for each device category tracked by Google Analytics: Desktop, Mobile or Tablet. It could also be easily adapted to display time-of-day vs day-of-week profiles for other dimensions such as Continent, Medium, of Social Network.
Inspired by a presentation from Gerry White of SiteVisibility
Download the workbook: GoogleAnalytics-TimeOfDay-DayOfWeek-2-0.xlsx
Can be refreshed with the Analytics Edge Basic Add-in and connectors.