I'd participate if I was still in my teens / twenties and had way more time. Instead, I will just observe and enjoy. I especially like the videos where they are counted out as the song actually plays.
I'm less excited about time sig changes as I was at that age as well (in terms of writing). The best thing about writing in multiple time sigs outside of 4/4 is that you are less likely to inadvertently copy something.
My suggestion to anybody getting into this is to not try to learn as many time sigs all at once. Instead, get 4/4 down. Then try and make 4/4 not sound like 4/4. That's how you know you have it as an internal clock as opposed to thinking in terms of numbers and subdivisions.
Then take just one new time sig and just jam over it. You've had a decade or decades of 4/4, so the idea that you are just going to internalize a new sig in an hour then move onto the next one is ridiculous. You can do it, but then it just feels like counting instead of feeling it.
I'd suggest taking this route:
12/8 - 4/4 with a triplet feel (subdivide by 3 instead of 4) Also called compound time (as opposed to simple time)
3/4 - The easiest way to feel this is think waltz. This allows you to *home base* the feel so it isn't just counting
9/8 - This is the same as going from 4/4 to 12/8. Instead it is 3/4 to 9/8. Waltz feel, but compound (3) instead of simple (2s and 4s) per beat. But you can take a different route and do the Voices intro (4/4 with half beat tacked on at the end)
7/8 - This is where you start to really get that odd time feeling going. Where the symmetry starts to go away. But it doesn't have to.
People can think of it as eighth notes divided into 2-2-3 or 2-3-2 or 3-2-2 or 3-4 or whatever. That's the common DT feel(s). But my love of 7/8 is when I naturally fell upon looking at it from the 16th note perspective. My absolute favorite pulse is
1 e & a - 2 e & a - 3 & a - 4 & a
So it feels like 4/4, but the 2nd half (beats 3 & 4) have the last 16th note chopped off, which produces a slightly rushed feel. This gives the illusion of 4/4, but for some reason it feels like it is really chugging along.
You can also think of it as 1st half simple time, 2nd half compound time. Or 2/4 + 6/8, but the 16th note equals the eight note triplet in time duration.
I'll cut it there, but just throwing out some thoughts on how to feel these as opposed to just counting them out. Maybe we can start a thread where somebody takes a time sig and explains how they feel it. There are some "accepted" ways, but the fun is not just using the accepted methods. If you stumble upon something musical, share. I'm thinking Mangini's The Grid might be something like this (just guessing).
Also, sometimes it is easier to combine sigs for the sake of the sheet music looking less "change every few beats". For instance, going back between 5/4 and 4/4 constantly, sometimes when you are in your DAW, it is just easier to say 9/4, even though the constant 5/4 to 4/4 changes represents what is actually happening better. It can be bad form, but oh so much easier to program into the DAW. I bring this up because of the 11/4 and 7/4 mentions earlier.
BTW, I'd like to see the songs prepared with two numbers each. One is every change. The other is every unique signature. I think that might give a different perspective into the complexity as well.