I am also a single, working mom and I usually cook on the weekends and eat alot of leftovers on weeknights. But, I always have a few really quick meals that I can put together quickly during the week too.
For recipe ideas Kraft puts out a quarterly magazine with lots of kid friendly recipes. It's free and you can sign up at http://www.kraftfoods.com/kf/FoodandFamily/ They also have a bunch of recipes on their website. You have to watch is because their recipes aren't always as healthy as I'd like but they are kid friendly. I am also a fan of allrecipes.com as a place to find good recipes. They have alot of crockpot recipes if you are interested in that route. Alot of times in the reviews, people will mention if their kids liked the recipe or not. I also subscribe to Everyday Food which has alot of good healthy recipes in it. I think the subscription costs me $20 per year.
I find too that when I don't feel like cooking, I can give my son yogurt, some canned or frozen vegetables and some fruit and he is very happy. Another quick meal that I like to make is baked eggs. Spray a baking dish with Pam and break several eggs (how ever many you think you'll eat) into the pan. If you're only making 2 or 3, make sure you use a fairly small dish (I use a 7 x 7 in dish for 3 eggs). Optionally, you can cut up some butter into small pieces to scatter on top. Season to taste with salt and pepper (adding a bit of thyme is nice too especially if you don't use the butter). Sprinkle with a little bit of mozarella and/or parmesan cheese. Bake at 400 degrees for 10 - 15 minutes or until the egg whites are set. Serve with canned/frozen veggies and some fruit and you're done. Or if you don't want to turn on the oven, just scramble the eggs, make some toast and have breakfast for dinner.
I'm also fond of meals where you marinade meat overnight and stick it under the broiler for a few minutes to cook it. Try this pork chop recipe with some steamed vegetables. My son likes it alot. It takes me about about 10-15 minutes before I go to bed at night to get the marinade started. You can even clean and chop your veggies the day before too.
Spice Rubbed Pork Chops
4 boneless pork loin chops, 1/2 in thick
1/4 c lime juice
2 tbl olive oil
1 1/2 tsp ground cumin
1 1/2 tsp ground cinnamon
1/2 tsp hot pepper sauce
1/4 tsp salt
1 clove garlic minced
Trim fat from chops. Place chops in a plastic bag in a shallow dish. In small bowl (I use a measuring cup) combine all ingredients except pork chops. Pur over chops and seal the bag. Marinate in refrigerator 4-24 hours, turning bag occasionally (I usually just flip it once in the morning before I go to work). Drain chops and discard marinade. Preheat broiler. Broil 3-4 inches from the heat for 6-8 minutes or until done and juices run clear, turning once halfway through broiling.
Note: If your chops are thicker that 1/2 inch, move them a little bit farther away from the heat and increase the cooking time a bit. They will be firm on both sides when they are done.