A neat project from Microsoft Research does some photo manipulations to change facial expressions. I tried it and some of them work better than others. It’s getting mostly 5 star ratings though.
Create funny facial expressions by poking different parts, unlock different steps and solve the final mystery! This app uses face-related technologies from Microsoft Research. For best results, please select a photo with frontal faces in good lighting condition.
• Tap your face to create funny facial expressions
• Multi-face detection
• Integrated with Pictures Hub
• Share your photos on Facebook, Twitter, SkyDrive or Sina Weibo
Of course it’s free and you can grab it here.