Going off of what Shana said, I'm one of the people who brings something else to do while I sit and wait for the cycle to finish. I typically bring my laptop or just use the notepad app on my phone to get some writing done. Whatever it is I have to do, I always specifically plan on bringing another part of my to-do list for the day along with me when I'm heading off to do laundry.
Several people said the same but my favorite tip is to shop the perimeter. All the processed, packaged foods that you don't typically need are in the middle of the store so if you don't go there you'll come home with only natural, whole foods :) I also always make a list, otherwise it's just pure chaos and I could spend hours in the store.
Like Nicole said, Lentils! Those are a huge staple for me. I also really love chick peas, almonds, and raw sunflower seeds. Also, if your goal is to build muscle, make sure you are consuming protein immediately after your workouts because muscle growth is dependent on "positive protein balance" and consuming protein right after a strength workout ensures that your muscle protein synthesis (or the repairing/ growth of the muscle) will exceed the muscle protein breakdown.