What is WebOS Ports?
Basically, it is the (Open) webOS "Community Edition" project. You will see some old references to WOCE for that reason.
Read about the supported devices here.
What is Open webOS?
When HP pulled the plug on what was left of Palm, it produced an open source version of the webOS that ran on the HP Touchpad. That is Open webOS. LG, who bought the Palm division off HP, sponsor it now.
We have some cool material on it here.
What is LuneOS?
LuneOS is the name of WebOS Ports' Open webOS. Lune refers to the user interface in legacy webOS, LunaSysMgr.
What is LunaCE?
Luna Community Edition. It is a Touchpad thing.
rwhitby August 2012:
LunaCE (formerly UberLunah) is a collection of all the best LunaSysMgr improvements for the HP TouchPad, rolled into a single installation package.
Help develop LuneOS
If you have made a worthwhile change, our Submitting Contributions instructions tell you how to get it pulled into the main line.
For an easy life, develop on Linux. Ubuntu 12.04 LTS 64-bit works well.
Instructions for building (or just downloading) an image can be reached by selecting a target device from the Devices page.
Notice that there is a LuneOS VirtualBox Emulator which you can use instead of a target device.