Inspirational Talks by TED

A long term favourite of mine - good old TED!.
TED is a nonprofit organisation devoted to spreading ideas in the form of short, thought provoking talks (typically less than 20 minutes long).  Starting as a conference for Technology and Entertainment it has continued with many high profile speakers from all over the world.  From Business to Science it covers a wealth of information and generally has something for everyone.
Give it a go, starting with the Most popular talks of 2015