For me, my high bar that I have yet to beat, was the time I pivoted the running OS (ubuntu) into RAM over SSH so I could unmount and image the boot drive without rebooting and loading a live USB (Which would have required a ticket with my provider to enable IPMI)
In the early 2ks, computer were ugly grey box with noisy fan and a hard drive that gave the impression a cockroach colony were trying to escape your case. I wanted to build a silent computer to watch Divx movies from my bed, but as a broke teen, I just had access to disposed hardwares I could find there and there.
I dismantled a power supply, stuck mosfets to big mother fucking dissipator, and I had a silent power supply. I put another huge industrial dissipator on CPU (think it was an AMD k6 500Mhz) and had fanless cooling. Remained the hard drive.
Live CD/USB weren’t common at that time. I’ve discovered a live CD distrib (I think it was Knoppix) that could run entirely from RAM.
I removed hard drive, boot on live distrib, then replace CD by my Divx and voila.
Having a fanless-harddriveless computer was pure science fiction for me and my friends at that time.