Not technically a sideload app but a way to *allow* you to sideload apps. Install this through the normal Ouya marketplace. Surf the Ouya filesystem and install APKs you've copied there. GameBoid - Gameboy Advance Emulator Works Great on OUYA GBCoid -

How to Sideload Apps on Ouya. It's possible to get apps from Amazon, Google Play or other stores onto your new $99 Ouya game console. Here's how.

ADB Sideloading Lineage onto your Ouya via Raspberry Pi. This tutorial assumes that you have already set up your base Raspberry Pi OS and that you are either operating locally on the Pi or via SSH from another PC. This tutorial dives into the ability to s