Vote here!
There are so many good FMs buried by the years that I'd really like to revisit some and get them the attention they deserve, where newer players might only be working through the list in release order and so never get to them. If I were to start a sort of book club where we as a community play a golden oldie (i.e. pre-2020) and revive discussion surrounding it, which mission would you suggest and how often would you want it to change?

I posted about it before, but I think the default tdm logo video looks outdated. For a (i.m.o.) better looking version, you can download the pk4 attached to this post and plonk it in your tdm root folder. Every mission that starts with the tdm logo then starts with the better looking one. Try for example mission COS1 Pearls and Swine.
tdm_logo_video.pk4

Kill the bots! (see the "Who is online" bar)

I finished DOOM - The Dark Ages the other day. It is a decent shooter, but not as great as its predecessors, especially because of the soundtrack.

What do you know about a 40 degree day?
@demagogue