I spend too much time on Facebook. Are there any tools that would allow me to get a Weekly Summary of the posts in my newsfeed that got the most activity?
So far, Facebook develops Facebook Insights.
Facebook Insights is a tool for those wanting to track user interaction on your Facebook Page. Facebook Insights can be seen by all the admins of your page and it can help you track the number of active users to better understand page performance. Page Insights gives page managers a number of aggregate metrics, including the number of people who like their Page, how many people see a post and how many people clicked the post.
Related with your question, Facebook only has that tool for your page, not your activity (even your log activity). Maybe, there was a tool tracking your activity out there which developed by someone. But, it's possible Facebook develops next tool for tracking your activity (your summary) like Twitter Analytics.