Serious Eats - seriouseats.com

Cold pasta salad with a vinegar or citrus-based dressing. Use whole wheat pasta if you want to healthy it up a bit. Cheese is a good addition, along with whatever veggies you like. Maybe edamame or other beans, as well. It's decently filling, and it can stay unrefrigerated for a while as long as you don't put anything crazy perishable in there. And you can vary the flavors a lot, so it's not the same thing over and over.

Depending on what time your classes begin, could you microwave something at work and eat before you set out? If you plan to eat between classes, I wonder if a wide-mouth thermos would keep soup, stew, mac-n-cheese warm from when you leave the house until when you want to eat. Perhaps you could take food to the office, heat it up there, transfer to thermos, go to class. Then a trail of dirty containers suddenly starts piling up at work, unless you use a heavy-duty freezer bag for transport, take it home the same day, wash it out, and reuse.

Are there microwaves available on campus where you could reheat a container of lasagne, rice and veggies, chicken and noodles, lentils and sausage, etc.?

I'm suggesting hot foods because it seems like you're just starting the fall semester, and you might enjoy something warm and filling in the evenings to come.

Study hard, do well!

I have to say, first of all, you have my sympathy--taking night classes is one of the things I miss least about being a student. When I did that, to be honest, rather than packing a dinner, to avoid being tired with a heavy meal and to break up the night, I would have two snacks rather than a full dinner--usually fruit and nuts before class, then something during the break (usually some kind of candy bar or cookie or to be honest).

Sometimes, in a few classes, the students would chip in and buy a dinner or snack for the break or before class, like pizza or take out from the local (very good) health food store.

Actually a bento box style container might be perfect for you.
Think protein, vegetable, fruit, starch. (and maybe dairy)

Nut butter or nuts, cheese cubes, cut up meats (chicken, sausage, etc.), bean salads, yogurt or hummus
Grapes, melon, citrus, apples
Raw carrots, celery, pepper strips, cucumber slices, cherry tomatoes, etc.
Pita, whole grain bread or roll, tortillas, crackers, pasta salad or peanut/sesame noodles (you get the idea)
Mustard, salsa, ranch dressing, or condiments of choice

Then things that ring your bell- cookies, brownies, pound cake, pickles, olives, tortilla chips, chocolate.....

If I had a place I could microwave the sky would be the limit. Something easy-- bean burrito.

@zucchini -- hehe, you must have read my mind about the dirty containers piling up at work! On class nights, I've ended up bringing a gigantic amount of food to work and eaten before heading to school, leaving the containers behind at work for the next day to bring home. Unfortunately, I have a significant portion of time between then and when I finally get home, and I'm usually ravenous by that point.

@fujimama -- I used to have the Chinese-style rice balls (fan tuan) for breakfast when I was a child, and your mention of onigiri brought that wonderful memory back for me.

Thank you so far for the suggestions and kind encouragement about school. Sympathy helps towards evening class :)

@avaryne: Thinking about it, I guess I'd branch out a little bit more, since you're doing this so often. (But this is tasty enough to serve guests as an appetizer, so why not you?) i.e., I'd vary the crackers and the cheese (smoked gouda, brie, havarti with dill) and add nutella or honey to the pb now and then. wasabrod with peanut butter is divine. Could also do some dried fruits (apricots, pineapple, papaya)

When all else fails, there's always Cliff bars and trail mixes....

I like the wrap idea. There are tons and tons of things to fill the wraps up with and you can wrap it up in foil to prevent leaks. There are so many different varieties of wraps and sizes as well.