I still have my official 4.10 Live CD. As a total oblivious person about the Linux world back then that was one of the biggest technology epiphany for me. Such a small thing yet it was just so mind blowing to run a full functioning OS from a disk that works everywhere (almost) in a "non-destructive" way. I've felt like a king to have my own OS with my own stuff on the locked down school computers. It was like finally I could do everything and it was thanks to Ubuntu
(even though I know since that Ubuntu wasn't the first Live distro at all)