Salesforce Release 50 is an awesome one.  Check out the details:

Lightning Summer 16 Release Videos
[Must / ~20 min / Salesforce.com]

Lightning Summer 16 Release Preview
[Should / Long / Salesforce.com]

Summer 16 Release Notes
[Should / Long / Salesforce.com]

My Favorite: the user switcher!  Simplify Salesforce Navigation with the User Switcher

CertifiedOnDemand.com is ready with site updates!

• Field security is now listed as “Read Access” and “Edit Access” instead of “Read-Only” and “Visible”: Security Overview
• Chatter Answers now replaced by Chatter Questions: Chatter, Communities & Portals Overview
• Added materials to reference ability to send from Outlook 365/Gmail:  Desktop and Mobile
• Trailhead link added for Getting Started Salesforce for Outlook: Desktop and Mobile
• Processes Can Execute Actions on More Than One Criteria: Workflow
• Global Picklists: Fields
• See how users are verifying their identity: User Setup & Login Process – Free
• Contacts to Multiple accounts: Sales Cloud