NP here.
Burrito bar is our staple. Kids love to make their own. Include any of the following: tortillas, beans (I usually mix pinto/black and whole/refried), tomatoes, lettuce, mushrooms, cheese, onions, cilantro, corn, olives, avocado or guacamole, salsa.

My kids love salad, but a simple one for kids who might not eat it all the time is dark green lettuce with strawberries and blueberries. Use a mild vinaigrette or flavored vinegar, and add a few shaves of parmesan if you like.

Cherry tomato and avocado salad. Add a dash of good EVOO and salt.

We also make sushi. Just thinly slice veggies and roll. Add a bit of cream cheese for some.

OP, kids generally just don't eat that well at social events (except dessert). Unlike adults, they are not excited about the food, and would rather be playing. don't take it personally! Do you like the Morningstar Farm products? My kids LOVE the "chicken" nuggets. So maybe you could offer them whatever the adults are eating but have them as a backup? When we have other families over, I let the kids make their own pizza using flat bread. Homemade mac and cheese is also a guaranteed hit. fruit (watermelon!), cheese and crackers would even keep them pretty content if they don't like what you are serving. generally speaking, kids don't like to see lots of mix-ins. So, mac and cheese is fine. Mac and cheese with peas, tomatoes, or whatever else is not.

13:54, I would love to hear more about the food you fix for your daughter. I am not vegetarian, but we do have vegetarian tendancies. Other than pasta, any other ideas you can share? If she takes her lunch to school, what do you send?

Well, I'm a vegetarian mother of a vegetarian kid, and you can't go wrong with pasta. Kids, especially smaller ones, do go on food jags, and mine (10) currently hates tomato sauce, but other than that, I think if it's relatively simple a kid will be likely to eat it. E.g., pesto goes over well with said tomato hater.

The previous thread about expensive foods and kids reminded me that I too have a question about feeding kids. I don't have any, and the only kid I cook for regularly is my niece who eats and appreciates all adult food. And growing up, I just ate what the adults were eating. So when people bring kids over, I'm always wondering what to cook for them that the adults will enjoy too. Parents often say "Oh, everything!" when asked what their kids eat, but I find the reality is different. Does anyone have any suggestions? I'm vegetarian, eat eggs and dairy, usually cook with a lot of vegetables, beans and whole grains. Some cheese is fine too, though I'm not a fan of cheese-laden lasagna/ enchilada etc.

Thanks!