Probably the most enjoyable iPhone app I've tried so far (and I've tried a lot) is RjDj (V. 0.6.5, Reality Jockey; $2.99 for each of its two editions, with a limited free version also available). Put on your headphones and select a “Scene,” which is actually a preprogrammed chain of effects that sometimes includes music tracks. When the sounds in the room or the sounds you're creating musically come through the microphone, they interact with the processing to create all sorts of interesting and unusual soundscapes with a wide stereo image (see Web Clip 2). The developers call it a “reactive” process. You can also record your RjDj session for later playback. The version I tested had no export feature, but Reality Jockey is planning one for its next update (which will also allow users to download additional Scenes). I experimented with playing instruments into RjDj and got some pretty cool results. It could be a useful tool for sound designing.