Dr.i.n.e. - Drine Is Not Emulator (following up on the idea of http://www.winehq.org/)
Drine is built around concept of UI-Bridging: Android's java API+xml is what the user (your) code compiles against, while each implementation of particular UI-bridge "emulates" the Android API on particular platform. Drine currently features two bridges:
1) Drine-SWT - intended to run Android activities on Linux/Windows
as normal desktop apps. Implements Android's APIs using SWT (Standard Windowing Toolkit from Eclipse)
2) Drine-A.W.Tk - nicked as "Android Web Toolkit" (no pun intended),
as the name implies, it lets android apps run as web apps (Activities Web Server + Browser with Ajax/DHTML)
For more info and some screenshots, check out Drine's Technical Overview
Java sources with samples and Ant scripts for Dr.i.n.e v-0.2 are under 'Downloads' tab
A screenshot of sample app served via Dr.i.n.e. deployed on Servlet 2.4 compatible container:
Project is in alpha stage, contributors and testers are welcome (contact me: neramybe at gmail.com). If you'd get stuck, see "Issues" tab for some hints, or report your problem there.