Suggestions for an interesting distro on a spare machine...

I've just ordered a new PC which will arrived complete with Ubuntu. I'm currently running Ubuntu on the this PC. Once the new PC is here it'd be fun to put something interesting on this one to run as a spare. Has anyone come across anything that might be interesting? A why would be nice too! :)

This currently copes with Ubuntu 23.04 without any issues; however, it has an unusual graphics card setup - Nvidia GeForce GTX 90 (x2) which Ubuntu doesn't really use to its full extent.