Make sure that you rinse the quinoa well first to get rid of the bitter flavor. My younger two won't eat quinoa either but my teenager will.
I love it with the cilantro and tomato and lime juice and you can put in corn, black beans, bell peppers etc...
I cooked some quinoa last night together with amaranth and millet and a little teff - I used 1/2 cup quinoa and 1/4 c. millet and 1/4 c. mostly amaranth with a little teff in it. I added a little more than a cup of water and then put chopped kale on top and some chopped up dried mushrooms in it and cooked it together and added a little soy sauce, apple cider vinegar, salt, sesame seeds and some sort of rehydrated seaweed (can't remember which one I threw in there). Dh and I ate it and liked it, but the kids probably would not have.
You can cook quinoa in broth rather than just water to give it more flavor. You can add any veggies you want to. I like to mix some amaranth and millet in with my quinoa because the quinoa has a strong flavor of it's own while the amaranth and millet are rather bland.
If you make homemade bread, you can add in a little bit of leftover cooked grains like amaranth or quinoa to your bread dough - you could even add a little bit in with banana bread if your kids like that.
I have found that the banana flavor of banana bread hides lots of good healthy foods that I can sneak into banana bread.