Alyson Hannigan celebrated St. Patrick’s day early last week with the cast of How I Met Your Mother. She stepped out in a Vena Cava dress which made her petite frame lean and elegant. To add a pop of color to her neutral-colored dress, she carried a B. Romanek Rock Star clutch in turquoise. The clutch came onto the scene in a big way last year and has chugged along ever since. The caiman skin clutch ...