The title says most of what this thread is about. Hacker conferences have very cool presentations and they share them with people. Not all are good but many are so share your favourites or ones you have recently seen. I am not going to be too hardline so if you want to share something from somewhere like http://www.eevblog.com/ or https://www.youtube.com/user/mikeselectricstuff/videos or even https://www.youtube.com/user/scamschool then feel free. There are many hacker and security conferences. Some of the most famous are defcon, C3 congress and blackhat. Smaller ones are not to be ignored though as they often have up and coming speakers and talks on more low level stuff I will start Lifts/elevators from the hacker perspective, might want a bit of lock/lockpicking knowledge at points. Introduction to TOR and the things you can find on it.