Yes. Paint the space under the curtains to look like a window scene. Or use an old window, complete with panes-backlit with a small light for 'daylight' effect and hang curtains. I had to do this in one of my rooms. keeps it from feeling closed in.
Think of a theme. Something that you and your friends are really into. What is it: Music? Movies? Fashion? Science? Games? A Sport? Work around that theme. Pick a color palette based on that theme. Like the colors of your favorite team, or a poster or picture you like, the cover of your favorite music album, etc. I would not pick any dark colors as base colors, unless your basement has egress windows. Basements usually receive very little daylight and for that reason, any color you apply on them looks at least 2 tones darker. I suggest you go for light, neutral tones for walls and floor and then splashes of color with furniture, drapes, upholstery, wall art and props. But before you start decorating, please make sure your basement is dry enough to be used as a living space. Get an inexpensive hygrometer to monitor the Relative Humidity in the basement. If it is anything at or above 60% RH, consider buying a good basement dehumidifier before you start to bring in the stuff. That is because at that level of moisture, when you start adding wooden furniture, fabric and paper to the basement, mold will start to grow. Your basement will start to smell musty and become unhealthy and uncomfortable. Mold needs moisture above 60% and organic surfaces to grow. You can't have all inorganic stuff in the basement, so you need to control the humidity. In addition, computers, TVs and electronics do not respond well to humidity, so if you plan to have a home theater or a game room there, you need to get rid of the moisture.
Do you know any artists? I think it would look really cool if you could paint a window and maybe a scene outside it on the wall, and then hang the curtains around it. That would look better than just curtains on a blank wall.
I was just in model apartment that had curtains on the wall behind the couch I thought it looked nice. I broke up what would have been a big and bare wall. If you like it go for it! Curtains are an easy way to change the look of a room.
