In high school I used to hang out in the computer lab after class, where my friends and fellow anime fans would use the school’s T1 connection to download videos of anime openings. After a while we started mixing and matching opening animations. with opening themes in a relatively crude fashion by having two video windows open and playing the video from one with the audio from the other. It was really fun and while I understand that the human mind will just associate any two things together like that, I still enjoy doing it.
For a while I was using Youtube Doubler to approximate the effect, but now I find out there’s something called “Tubedubber” which does exactly what I was hoping for, allowing you to stream the video from one Youtube clip with the sound from another, and it even has enough settings so that you can time it properly.
I particularly enjoyed combining Gundam X with Gaogaigar back in high school. The only flaw is that the audio ends before the video, so your only choice is to pause the video as the song ends. Currently, I’ve gone with something decidedly more patriotic.
Try it out! It’s also a fairly low-level way to make some super basic AMVs.