I can't wait to wait to wear this shirt while trick-or-treating with my kids. Spreadshirt designed it for homeschool moms and I LOVE IT!
Leslie from KindergartenWorks created more cute designs, including some with subway art, such as this one.
Leslie also has an entire shop dedicated to school teacher shirts that completely rocks- Teacher T-shirts. If you teach in a classroom, you have to check it out.