Here is a list of meatless dinners that my kids will eat, and a link to one of my favorite food sites.
Colcannon: we like this the traditional way, with potatoes and cabbage and lots of butter, but it also lends itself to some good variations, like using kale with the mashed potatoes instead of cabbage. Even further afield, but also delicious, is mixing sauteed chard with previously roasted potatoes. Saute the roasted potatoes in butter and smash them a bit with a spoon before stirring in the sauteed greens.
Falafel: I like to make this one in the Crock Pot and have it ready when we get home. Yogurt and cucumber salad is delicious alongside. We can serve it with pita bread or without. Fresh pico de gallo is also good.
Vegetable Soup: This is just your basic puree of vegetables with good stock, and can be mixed and matched in so many different ways. One way way to make an almost-cream based soup is to puree one vegetable (like broccoli)with a potato or two, and adding evaporated milk instead of cream.
Quinoa with vegetables: This one can also be done in 5 minutes if you make the quinoa earlier in the week, and just reheat and fluff before adding the vegetables. Don't forget to wash the quinoa well - with at least two changes of water. It should not taste bitter or strange at all. You'd be surprised how many people forget to rinse it.
Lentils: There are as many different versions of this as there are of lasagne. Our favorite lentils are the small green ones from Spain, but black lentils and french lentils are good too. Funny that the small green ones from Spain are cultivated in the US and imported to Spain. Can't find them here!
Barley Soup: I like to add barley to carrots and mushrooms sauteed in lots of butter.
Spinach Pie: This is based on delicious spanakopita filling, but uses a quick pre-made pie crust to get it in the oven in about 7 minutes.
And a little song.