what do y'all actually host?

hi there, comrades! just curious, what do you all actually host for yourselves?

i currently run a two old PCs refurbished as Ubuntu servers and am looking at adding a Raspberry Pi 400 that i was gifted and don't know what to do with. i have ideas though!

anyway, i'd love to hear what you've found useful, helpful, and/or fun to run. my own answer will be in the comments.