Ubuntu Launcher 0.5.5 is an app launcher developed for Android devices, which aims to bring the Unity functionality to phones.
Many users might have something against the Unity desktop environment that's being used in Ubuntu, but the truth is that Unity comes with a great app launcher. Coincidentally, the same kind of launcher might work very well on phones and a similar implementation is being done for Ubuntu Touch.
It's going to be a few months until Ubuntu for phones is available in stores, and even then not all Ubuntu fans will get the chance to have it. Fortunately for them, a developer named Robin Jacobs made a launcher that works in Android and that bears a striking resemblance with the one that you can find in Unity.
The installation is simple and it can be done from Google Play. The application is free, but it's still in Beta and that means bugs are bound to happen. As you can imagine, it's possible to set it as the default launcher and completely transform your system.
It's very fast and doesn't seem to hog the system resources. Until now I didn't have any particular issues with it, but some users have reported various problems. If you do find a bug, make sure that you contact the developer and tell him about it so he can fix it in the upcoming versions.
This project is not associated with Canonical or Ubuntu, so don't go complaining to them.