Carmelito Andrade has written an excellent tutorial in which he uses the Adafruit Capacitive Touch HAT together with a Raspberry Pi Model A+ and some 3D-printed bits to create a Pi-powered drum kit. Read it here.
Dr Scott Baker has been messing around with VFDs (Vacuum Fluorescent Displays) which emit light directly rather than being backlit like normal LCD displays. He has worked out how to interface such a display with the Raspberry Pi and has blogged about it here, including giving a listing of a small Python library you can use.
Newcastle-based Darren has written a tutorial that covers installing Apache Spark on the Raspberry Pi. Spark is a Scala library that is used for the analysis of so-called “big data”. This is the first in a series of posts and his next will deal with setting up a cluster of Pi 2s to do fast, distributed analysis. As he points out, it has to be the Pi 2 due to the increased memory and multiple cores, and it is limited by the specs of the machine such as the comparatively low throughput of the network interface. Read more here.