Some of the most popular Linux youtube videos by view counts –

1. Introduction to Linux
Linux history, what an OS is, how to interact with Linux, Linux distros etc.

2. 3D Desktop! TouchScreen and XGL on Linux!

3. How Linux is Built
The code, how many lines of code the Linux kernel has, how release are made …

4. Linux Baby Rocker
Baby rocket shell script, which ejects and pulls back a CDROM drive acting as a baby rocker.

5. Introduction to Linux and Basic Linux Commands for Beginners
Tutorial on basic Linux commands, the Linux in the demo is installed in Windows running a virtual box.

You can search full list in youtube.