To celebrate Friendship Week, here are the top apps Intel AppUp® center that value teamwork. Unite with your favorite Angry Birds to save their homes and chicks from the enemy pigs. Save Earth by combating the relentless space chickens in Chicken Invaders 4. Eliminate underground-dwelling monsters with your teammates by downloading Dig Dug. Read about the unity and rise of chivalric knights with Britannica Kids: Knights & Castles, which, as a bonus, was designed to help with homework and projects.