Feel like a Roman holiday? Drop in to Porsena and tuck into the best pasta you can find in Rome --- sorry! New York.  Porsena is a trattoria in the convivial Italian tradition where friends and neighbors gather to enjoy a pasta-centric menu featuring Italy's finest artisanal pastas, served with traditional and imaginative sauces. No change received on purchase.  21 East 7th Street. Expires May 4, 2013. www.porsena.com