To prep I simply added a few extras to our usual weekly grocery list. I wouldn't want to pulverize all of our green veggies into smoothies. Then what would the kids have to go with their pizza.
I washed, cut and sorted out a few days of fruit and veggies for the smoothies. There are a ton of recipes out there and each combination contributes to our mental and physical health in various ways. To keep it simple I'm starting with fresh spinach, fresh cubed pear, 1/4 water and two ice cubes. 
This combination is said to give energy, help detoxify as well as aid digestion and manage weight. I'm getting everyone on board. Hubby likes the spinach and pear too. I think it's a great 'gateway' smoothie. Wait till he gets a load of the Kale and Swish Chard :) * blends.
We have a Ninja mixing system but any blender will do. Just be sure to cut and core your veggies according to your systems capabilities. Before we got this one I worked the crap out of a Rival.
>insert awkward wicked laugh<
The kids have always loved smoothies. But they like the berry banana yogurty yummy ones. As do I. It's the "green" smoothies that are a hard sell. Apparently they all love this apple and carrot combination.
I'm hoping to continue my green smoothies beyond the thirty days; you know they say once you do something for 21 days it becomes a habit. Well....Cheers to day one!