Bust out your blender.
I've been adding veggies to my veggie-challenged husband's food for over a year now and he has never EVER said anything about it. One time, my record, I had 17 veggies total in some pasta sauce. And it tasted just like the pasta sauce I usually make. I'll blend squash, spinach, peas, carrots.. you name it, together and add it to chili, pasta sauce, soups, stews, stirfry, lasagna... whatever I'm making and it tastes darn good, lol.
Good luck! You might also want to try googling sneaky chef or that seinfield gal that hides veggies in kids food. I checked her book out of the library and it helped TONS.