Here's my wtf idea...
"Together Seasonal Retro"
What does that mean? This will sound silly, but hear me out guys. So four seasons; spring, summer, fall, winter. During each season, you try to play a game(s) that is both retro and somehow related to the current season. That can mean playing games that are related to the nature aspect of the season, or holidays that fall into said season. I admit this sounds corny at first, but I had a lot of fun doing this last summer and this past fall.
During summer I tried to find games that were tropical or ocean related, and during fall, played games Halloween related. Not only was it fun to play stuff that felt seasonably relevant, I also had to go out of my comfort zones to find retro games that fit the themes. I really did have a lot of fun doing this, and learned about lots of retro games I didn't know existed as a bonus. I think other people would have fun doing this too, if they tried the concept. For example, this winter I plan to play through five winter/Christmas related retro games.
Believe me, I know this sounds ridiculous at first, but it is fun once you start doing it. I think the problem with normal Together Retros is it's hard to pick out one game that lots of people will want to play. But this seasonal concept is open enough that people can choose their own retro games, as long as they fit the current season. And due to the common seasonal themes, there is a sense of community to the endeavor.
Just an idea!