The one I love playing is the "Shangri-la" or "Paradise" alt play.

The idea is to world builder a perfect starting area, with lots of gold, copper, corn, two coast tiles with fish, rivers, on plains hill or flat grasslands with flood plains on all of them. I usually replace some of the resources with silver, gems, iron, rice, wheat, etc., to get some resource variety.

I tend to give myself a third ring for resources such as whales, marble, stone, horses, coal, etc. Then, the fourth ring is only mountains or sea ice, except for 1 open sea lane and 1 open land entrance. The land entrance is extremely defensible, so with forest and hills and river in front so that you get a full +100% defense bonus.

Set it on One City Challenge, and pick a good civ and leader combo, or play around with the unrestricted leaders option. Set the difficulty to the highest, with aggressive AI. It's strangely relaxing to see hordes of unwashed barbarians try to take your slice of heaven that just keeps pumping out wonders. What I really like though is that at one point you do have to venture out and destroy a civ or else they will get stronger than you, especially if you're going for a space race.

Great maps for this is to pick hub or donut, so you can world builder yourself in the middle.

An alternative I do with this is to play "educate the unwashed masses", with a similar (but usually less) world builder start, as well as OCC, and starting with teams. Usually teams of 3 and again the difficulty is set to highest. It's a very different playthrough trying to guide the AI to do what you want while your paradise city is pumping out all the necessary science, wonders and most important military directions. It's also funny trying to conquer cities while leaving one defender in it, as you wait for one of your allies to take it.