I probably made my most niche thing ever today: A plugin for an Android app. I found out yesterday that a new API for Yatse was made available, so today I took on the challenge, and created a plugin for my Denon A/V receiver. I can now control the volume on my receiver directly from Yatse. In a few days I might clean the code up and finish it, so it can be released either here or on Google Play.
Denon receiver plugin for Yatse