Most of the focus has been around training people for the 70-461 exam certification.
Full Length Free SQL Server Training Videos
Some of these are full length at around an hour to an hour and a half like this one on Time Functions, Logical Functions, and User Defined Functions.
Other videos are short and focused on a specif topic like this one on Using the TSQL DATEPART Function at just under 3 minutes.
Take a look, enjoy the videos, and hopefully learn something along the way. I hope that sharing these Free SQL Server training videos will help you become stronger at your SQL Server skills.