What is WebOS Ports?
Basically, it is the Open webOS Community Edition project.
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.
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, clearly. 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.