Google provide such emulator. Ubuntu could at some point run Android apps, but they gave up before Android 1.6 was released. The problem with recent Android is

Google provide such emulator. Ubuntu could at some point run Android apps, but they gave up before Android 1.6 was released. The problem with recent Android is that most apps require the full system with all the services / contentproviders. You can download the playstore APK or individuals APK if you wish. The second option is to run the x86 version of Android in a VM or chroot + VNC (linux only). Apps using the NDK wont run, but you will get native-ish speed for the apps that does run. As for an "integration mode" where many apps can run in parallel with their own WM client, I don't think there is something for that yet.