Designed this using mainly the pathfinder tools in Illustrator. 
 To create the stripes:

1. Type in your text that you want to be a stripe
2. Make your stripe shapes, then select all of the stripes and in the pathfinder window, hit Unite 
3. With the text layer selected, click Make Compound Shape, then Expand (in the Pathfinder window)
   
4. Place the stripe layer over the text layer
5. Select both the type layer and the layer with stripes, and hit Minus Front from the Pathfinder window (make sure the stripe layer is above the text layer

Note:
To create even stripes, use a grid.

1. Draw a rectangle about the size of your work area.
2. With the rectangle selected, click Object > Path > Split into Grid...
3. Change the number of rows and columns to make the size equal to what you want the size of the stripes to be (clicking preview will help you visualize) Click ok
4. Right click on the rectangle and choose Make Guides
5. You will now have guides that you can use to draw even rectangles within to create stripes

Finished Book 5 in Harry Potter series.  I'm only nine years late.  Simple illustrations to commemorate the occasion.