Personalized Keep Calm Polka Youth T-Shirt. Funny novelty Polish music, German music, polka music, accordion lovers, polka band Youth T-Shirt - White with accordion graphic says KEEP CALM POLKA ON. Gifts for polka lovers, oompahpah, squeezebox players, polka bands and festivals. Let the good times roll in a durable T-Shirt that takes kids from school to play in an amazing array of colors. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar.