[LG Optimus 4X HD] arararagi:
This is completely compatible with the official CyanogenMod 10.1 (and I'm planning to keep it that way), so you can switch to and from official without any problems.

The main focus of this ROM is to stay up to date with CyanogenMod 10.1 git branch and add features that allow finer grain customisation of hardware specific to the 4X.

What's added:

LG QuickMemo (hold Vol+ and Vol- to activate) [framework change]

Enable wake by pressing volume key setting [settings app change]

Control button backlight in System Settings (can stop it turning on whenever you touch the screen) [settings app + framework + hardware library change]

Button backlight used as notification light (can be enabled/disabled in System Settings) [settings app + hardware library change]

Button backlight used as battery light (recommend disabling in System Settings) [settings app + hardware library change]

Ability to dim backlight more than minimum (activate from ArararagiToolbox, otherwise like stock) [kernel change]

Ability to force fast charge even higher than default AC levels (activate from ArararagiToolbox, otherwise like stock) [kernel change]

20130502: Fix headset button (thanks to Wenque) Now in official CM

20130505: Disable baseband_xmm_power wake lock [kernel change]

20130512: Torch brightness control. You need to clear data for the Torch app. Default is the minimum possible brightness, rather than the stock CM 10.1 brightness. [Torch app + kernel change]

20130515: Fix known issues in torch brightness control caused by 20130512 changes. Clear Torch app data. [Torch app change] Disable touch debug printing in kernel. [kernel change]

20130602: Use new vibrator implementation in line with CM. Add baseband_xmm_power wake lock back in.

20130609: Uncap screen brightness

20130611: Disable baseband_xmm_power wake lock again. Now using Linaro 13.05 GCC 4.7 to build (user + kernel).

20130612: HALO ported from ParanoidAndroid

20130613.1: OpenPDroid

20130623: Enable ODEX

20130623: Use -O3 for compiling native components

20130623: Increase vibrator PWM duty cycle (should increase vibrator strength)

20130625: Tweak background process parameters

20130630: Add QuickMemo quick settings tile

20130707: Add LG Hidden Menu (only GNSS Test works at the moment)

20130713: Allow control of which backlight HVLEDs are enabled. Lets you make the screen even dimmer

20130716: Allow control of gamma LUT from user space. Let's you over saturate the screen colours

20130727: Add support for external GPS (http://review.cyanogenmod.org/#/q/owner:ich%40morphew.de+status:open,n,z)

Check github for full changelog. Each release also includes changes from official CM.

Optional (can be installed as normal app):

Memobin.apk: LG Notes

AraragiToolbox.apk: Actually activating some of the features mentioned above

CameraApp3.apk: 20130606. LG Jelly Bean stock camera app ported to Android 4.2/CM 10.1.

ArararagiToolbox features that work on any ROM:

Check battery current (drain/charge in mA)

Disable USB (for charging on untrusted computers)

Check KSM (kernel same page merging) stats

Note: Anything changed from AraragiToolbox won't stay across reboots, as it's more of a tool for testing. I'm planning to add them into the System Settings later on.

Install by flashing zip from ClockworkMod (Find "Optimus 4X" on the page). No need to wipe data if you are already using CM 10.1.

Download: cm-10.1-20130727-UNOFFICIAL-p880.zip (md5sum: 99d7acca2d33fcdac8c6faed57f44f0b)

Source: https://github.com/mzhou/arararagi_lge_p880_patches

Planned:

Overclocking, Schedulers, I/O Schedulers, Governors

Vibration strength Make it configurable

Control camera flash/torch brightness

USB mass storage

Fast charge tile

How to HALO:

See http://xdaforums.com/showthread.php?t=2117444&page=976 (Thanks to kubics for original posting and Namor Noditz for linking) on how to configure.

Just mentally replace "Settings > RootBox Settings > HALO Settings" with "Settings > System".

This YouTube video goes through all the gestures: http://www.youtube.com/watch?v=d5WljHcOyXs