nop90 does a great service to the Nintendo 3DS community by releasing a greatly improved port of libSDL. This should raise the library of Nintendo 3DS homebrew games really fast! Read more about SDL-3DS v0.9-1.2.15 (3DS misc Port)
ctrmus is a music player for the Nintendo 3DS. For now it plays PCM WAV, AIFF, FLAC, Opus and MP3 files. Due to limitations in ctrulib, only ASCII characters are displayed correctly. Other characters will appear garbled, but functionality is not affected. Read more about ctrmus v0.4.12 (3DS Application)
EasyRPG Player is an open source implementation of the RPG Maker 2000/2003 engine. Get a RPG Maker 2000/2003 game and place the Player (boot.dol) in the root directory of the game (that's where RPG_RT.exe is). The program has no file browser, each game really needs its own boot.dol! Read more about EasyRPG Player v0.5.2 (Wii Port misc)
opsu! is an unofficial open-source client for osu!, a rhythm game based on popular commercial games such as Ouendan and Elite Beat Agents. It is written in Java using Slick2D and LWJGL, wrappers around the OpenGL and OpenAL libraries. opsu! runs on Windows, OS X, and Linux platforms. A libGDX port additionally supports Android devices. Ported to Pandora by ptitSeb. Read more about opsu! v0.15.0.08 (Pandora Game Port)