You could start a scrapbook or photo album if you haven't already. You can use photos of ultrasounds, your growing belly, his nursery, baby shower guests/gifts, etc. Put descriptions of each and if you're not crafty like me (I don't do paper cut outs, punches, or anything that requires a lot of creativity), you can make a photo album cute with fun stickers or some scrapbook accessories. You can also buy one of those scrapbook kits where it's all laid out for you and all you have to do is put your photos in and glue or stick other stuff down like they suggest.
You could do a craft kit and make something for your son's room. Paint a photo frame, sew a pillow, paint a piggy bank. They require effort and attention, but the skill level is up to you how elaborate you make it.
If crafts aren't your thing, you could write a letter to your son that he can read when he's older. You can either write it just now or keep adding to it over time.
Sleeping is a wonderful idea!!! Enjoy the quiet while you can.