I constantly hear about how the moon has water in a crater on its south pole. This gives me an idea of building a base in the north pole.
The moon, unlike the Earth, is not tilted. The poles of the moon have perpetual sunlight...except that the south pole is a crater that lives in perpetual shadow. Hence the water. (With no atmosphere, the moon is burning hot where the sun shines and freezing cold where it doesn't. Ice remains in the shadows.) So my idea is to build a huge megastructure on the north pole (especially if there is a crater there), topped with a giant geodesic dome made of Plexiglas. I imagine this structure being many cubic kilometers in size, at least the size of Rhode Island. In the geodesic dome, there will be a park and a farm. Below, a living area and a laboratory and a huge storage area, and some sort of airlocked shaft to the lunar surface for resupplying.
I imagine the lab being used for fusion research, as the lunar surface is covered with helium, and the farm growing the food that the fusion scientists would eat. Also, it would grow tobacco. Why? Interesting reason for that.
On our third trip to the moon, one of the astronauts was a major conservationist and brought a collection of seeds with him. When he came back, these seeds were quite popular with people who desired the novelty of a "moon tree." There is nothing odd about the trees other than the fact that as seeds they were once on the moon. (This has not changed them in any perceivable way.) If people like "moon trees," I'll bet they'd go absolutely gaga for "moon tobacco." Now you can smoke something...that grew in the perpetual sunlight at the lunar pole. Holy crap!
One other project to develop would be to send astronauts to the far side and have them construct a telescope there. Communication wires would then be installed to link it to the moon base, and then to Earth-based radio link. This would be an excellent vantage point to observe the universe, and I imagine a major jockeying of astronomers for a share of time to use it. (Only really useful when the moon is full, and the telescope not facing the sun, unfortunately.)