Jon Goff has a very interesting post about the design of a relatively low cost, tethered rotating space habitat for the study of the bio effects of gravity at levels between 0 and 1g: Variable Gravity Research Facility (xGRF) – Selenian Boondocks.
I’ve recently been thinking that a one turn per orbit habitat on a long tether could also be a good tourist facility. Even a low fraction of 1g makes many things simpler, e.g. fluids will flow so the design of life support systems gets a lot easier, and may ameliorate the health hazards of 0g (need Jon’s xGRF to study this). However, a fractional g, near-weightless environment would still provide a lot of fun. A big window “looking down” onto the earth would offer a wonderful steady view.