We eat tacos just about every week. I cook turkey meat with some (very small chopped) onion and garlic, plus cumin, chili seasoning, and a little curry powder. Then I put bowls on the table that each have one ingredient-- tomatoes, beans, lettuce, salsa, cheese, chopped broccoli, etc. Everyone gets a soft whole wheat tortilla and can fill their own with the ingredients they choose. At this point, my son mostly eats the meat and cheese, but as he grows, after watching us eat healthier and "just trying" a few bites of other things, his palette will expand-- it worked for my brother and I!... I also cook risotto with chicken sausage and veggies-- picky eaters can eat around the veggies. For sneakier options, check out Missy Chase Lapine's recipes on this site:
http://www.education.com/magazine/column/Sneaky_Chef/