[In this weekly feature, Gamasutra rounds up the week's most popular paid and free iPhone and iPod Touch games, as current on the iTunes App Store.] This week's top paid iPhone game titles on the App Store, as captured on May 17th 2011, are as follows: 1. Angry Birds ($0.99) 2. Angry Birds Rio ($0.99) 3. Tiny Wings ($0.99) 4. Words With Friends ($2.99) 5. Fruit Ninja ($0.99) 6. Where's Waldo? ($0.99) 7. Doodle God 8. Cut the Rope ($0.99) 9. Angry Birds Seasons ($0.99) 10. Army of Darkness Defense ($0.99) Rovio's Angry Birds and Angry Birds Rio once again dominate App Store game sales, though Andreas Illiger's Tiny Wings reports a surge in popularity this week that lands it ahead of Words With Friends at third place. Ludia's Where's Waldo? and Joybits' Doodle God return to the latter half of the top ten after extended chart absences, as Backflip Studios' Army of Darkness Defense earns tenth place in its debut week. Here are this week's top free iPhone games: 1. Rat on a Skateboard 2. MetalStorm: Online 3. Look Again! 4. UFC Undisputed Lite 5. Office Jerk 6. Marshmallow Cookie Maker 7. Angry Birds Rio Free 8. Stickman Skater 9. Pandadog Defense Lite 10. Words With Friends Free Donut Games' Rat on a Skateboard wins today's free chart during a limited-time free download promotion, edging out Z2Live's aerial combat game MetalStorm: Online for the top spot. Smappsoft's puzzler Look Again! and a free trial version of THQ's UFC Undisputed also rank as popular downloads this week, pushing former chart leader Office Jerk to fifth place in today's results.