JosephEarnest has taken a Raspberry Pi 2, a USB digital-to-analogue converter (for sound output) and some other components soldered to stripboard to create a midi input/output device. The software is written in Python and cython and is available here. He’s made the whole thing open source on his website where you can read more and, perhaps, build it yourself.
Roo Williams was tasked with improving on a company’s method of taking ID photographs. What he came up with was a Raspberry Pi with a camera module which talked via a Flash web interface to the subject’s mobile phone. He also hooked up some strip lights via a relay board to act as a flash. Read more here.
Mario Lukas’ girlfriend is an archaeologist. Part of her job is to catalogue relics from digs and Mario deduced that what she could do with is a handheld, portable 3D scanner. So, he decided to build one using a Raspberry Pi 2, a Kinect scanning bar and a PiTFT. He’s used a library called Libfreenect on the software side and is currently at the proof-of-concept stage. You can see a video of the proof-of-concept (you might want to mute the audio – it’s a bit offensive on the ears) and read more here, including a link to instructions to help you compile the library you need.