Play an 80s synth in your browser with 106.js, a MIDI-enabled emulation of the Roland Juno-106 synthesizer. Chrome/Desktop only. Github repo here.
I have recently written a MIDI control surface app for the iPad. It currently has six layouts, consisting of combinations of piano keyboards (with pitch bender), and ribbons and XY pads, which can be configured to send different MIDI control events. It works over WiFi, talking to the open-source DSMIDIWiFi client. [more inside]
To quote myself from the page: "Most MIDI keyboards look like cheap toy spaceships from 1982. But music production is now a home activity. Here’s a keyboard you'd be proud to have around."
This a language that uses MIDI, instead of text, as source code (it's NOT a language used to create music). I tried to allow enough flexibility that you could compose something that both sounds good and works as a program. [more inside]