I've been wanting to try this idea out for a while now, I just hadn't had the chance. One of my friends' son had a birthday party this past weekend. I thought it would be cool to make it for him. (And one for CalJ too).
Ch-ch-check it out...
Make a freezer paper stencil with the initial of your choice and iron onto shirt.
Spray bleach onto shirt around initial using the "fine mist" setting on your water bottle. Then use the (for the lack of a better word, I'll call it the) "squirting" setting to spray finer lines in random places all over the shirt.