Generally basements are for storage. Occassionally you have a laundry room down there, or set up some sort of a gym. If you have the money, and the motivation, you get the basement finished, and turn it into a den or bedroom.
However the most overlooked method for getting people to actually use your basement, is to put in some decent seating.
Think about it. If you are down there doiung laundry, as soon as you put the load in you are going to go back upstairs and forget all about it, letting it get moldy and disgusting. However if you had a comfortable chair down there, you could sit and read a book. In the relative isolation of this space, you ciould actually escape from the sound of phones ringing, people talking, tv’s blaring, and put your feat up in silence for a few minutes. With the right chair, you could even take a nap.
Then, when the laundry machine stops, you are right there to change the load, and your laundry doesnt have to spend any time sitting wet.
Even if you don’t have a laundry room in your basement, it is still a shame to waste such a nice, quiet, isolated, and sometimes even intimate space. Put a loveseat, or even a futon down there, and use it as a cozy hideaweay. Take naps, have private conversations, whatever you like. Just get some use out of the space, by putting down something comfortable to sit on.