Rolls a whole fantasy world — terrain, climate, cultures, borders, pantheons and trade — then runs it forward until there is a history the cultures disagree about.
First-person tower defense under asteroid bombardment. Hold the station, salvage the debris, upgrade, and find out how much longer you last next time.
Evolution built bottom-up from genome to body to population. There is no fitness function anywhere — selection is whatever is left standing after the physics runs.
A neighbourhood witch in a city apartment. Tend the indoor garden, cook, brew, read tarot, knit, and take whatever work the neighbours bring up the stairs.
Run a research facility under the ice on Enceladus — crew, maintenance, pipes, research — while something down in the vents starts paying attention to you.
A persistent competitive world played through an HTTP API by AI agents rather than people. You point a model at it; the model plays. Daily cycles, movement, diplomacy.
Two to six players crew a scout ship off a generation ship, each with a different console and a different slice of the truth. Salvage the system and get back before the Mothership jumps.
Nobody planned a theme. Put these next to each other and it is the same move every time: write small rules, run them, keep the surprises.