Breakfast could be a great time for veggies if you feel like getting up early to grate zucchini, carrots and other yummies for baked/fried 'pancake' type foods.
If it were me, though, I'd serve the veggies with hummus at lunch or snacktime. Raw veggies are fine: red pepper strips, carrots, cukes as you had suggested. My son likes it when I pack up a few strips of red pepper and some olives for his preschool lunch.
You can also make an extra large stir-fry at dinner and serve it as leftovers for lunch time. In fact, many veggie dinner items can be served at lunch. Or a vegetable chili for lunch also works: let the kids make some cornbread from a mix and put them in muffin cups, to add a little novelty.
Noodle soups are good for veggies too. Carrots, celery, potatoes and beans are often well-received.
You can also do a 'salad bar' type offering where lots of veggies (celery sticks, olives, peppers, carrots) are presented with a couple sauces and some pita wedges, some cheese cubes, etc. If you put up a sign that says "salad bar" or do something else to get the kids to think it's special, even better.
I guess I've learned that unless I'm going to puree everything (and I'm not, as I need a new blender!), it's more interesting for both of us (my son and I) to see the veggies and talk about them. Having kids help as they can with the food prep is fun too, and gives kids a 'safe' experience with new foods, by touching and smelling them first before eating them at the table.
I'll be peeking at other answers too; always looking for new tricks.:)