Boil some broccoli and cauliflower to make them softer. Then mix in the blender with water, and some plain yoghurt too, if you want. Add some sweetener (Splenda, or other). Actually taste pretty good :)
Drink as a sweet drink after dinner, in the evening, for breakfast/lunch/inbetween meals, or drink with dinner (along with the chicken/fish/steak, protein part of dinner, instead of having vegetables on the side).
If you use less water, so it's thicker, you can use it as purée along with your dinner.