Essentially go for a walk and pick a few flowers and leaves. I don't about you but this sort of "nature walk" can take an hour with my kids so don't forget water and sunscreen.
When you get home, break out the glue and markers (and glitter because what fairy doesn't have glitter?) and make a flower fairy.
Here's a picture from Family Fun's site for a little inspiration:
|Photo from Family Fun|
Just let your kid glue stuff down and then use all that pent up creativity to make a fairy. Or a fairy boat or a fairy house or a fairy pet ...