I've been toying with an idea for ages that I think could be pretty fun but I want to make sure it's not wildly unrealistic before going too far with it.
The idea is that the Equator is fiercely hot, no human can pass over it unaided and the poles are temperate, habitable etc. This is possible (I hope!) because I have an Earth which is slightly closer to the Sun (smaller orbital radius) and has 0 (or close to it) axial tilt.
The closer distance to the Sun combined with the lack of tilt could cause the Equator to become much, much warmer than it is now and have the poles at a more reasonable temperature.
One thing that comes to mind is that there will be periods of vast daylight and vast night time as there is now in Northern Scandinavia/America due to the glancing angle of the Sun in the higher latitudes, but are there any geographical/physics reasons why this won't work (various amounts of fudging and hand waving permitted.)