"KrayFilters" was the first thing that came to my head…
Just a quick little GPUImage hack. Created in about an hour.
The app works with about 20-24FPS on iPhone 5. Other devices not tested, will most likely be slower.
You need CocoaPods installed.
git clone https://github.com/mglagola/KrayFilters.git
cd KrayFilters
pod install
open KrayFilters.xcworkspace