Perhaps my favorite comet up to this point was Shoemaker-Levy[1]. In the nascent internet days, I was working for a company that took interesting things online (such as shareware[2]) and packaged them onto CDs for people who didn't have pipes as fat as our amazing 56k dedicated line. I built a CD of images of Shoemaker-Levy slamming into Jupiter. I was in awe the entire time[3]. I can't even imagine the colossal energies those impacts created.
1. https://en.wikipedia.org/wiki/Comet_Shoemaker%E2%80%93Levy_9
2. Another thing I convinced the owners to do was put together a Linux CD. That laid the foundations for what would eventually become Turbolinux[3].
3. And, even though the interface was in Visual Basic, I was still happy with the output.
4. https://en.wikipedia.org/wiki/Turbolinux