Well...

On old RPG I was briefly in an RP that was all about dolls. Yes, dolls. Players played dolls. It didn't last incredibly long, but I loved the concept and still do.

I've played a lot of interesting roleplaying games IRL. I've played as a Medic in the Vietnam War, except with ghosts and monsters from beyond the veil getting involved. I've played as a 12 year old witch in a team of kids investigating the paranormal (one of whom was a bully that beat up his own goddamned dad). I also was in a weird Gundam-style game where we were on a giant mothership heading for Earth except our Mothership had a whole level that was full of Medieval knights. Oh, and there was this one time I played a halfling Romani-themed mage that manipulated Fate and threw cards like Gambit. Good times, good times.

I'm running an RP right now called Masters of the Hidden Valley that's not weird on a theme level but IS weird on a mechanical level as an NRP. There's some player conflict, but everyone is technically on the same, and everyone wants their clan (they're all part of the same clan) to grow together, etc. Thus far, it's turned out pretty well, and I love how my players are adapting to the whole "Irish clan that follows tradition strictly" thing.

I once briefly convinced someone to let me play a talking sword in their tabletop RP online. That was fun. I want to do it again.