Those sporting a Nexus 5 are amongst the lucky few to be running Android 4.4 Kit Kat at the moment, however that doesn't seem to have stopped some from tinkering. With that in mind, we have already seen details about how work has begun on CyanogenMod 11, which is based on Kit Kat -- and now it looks like an unofficial release has been made available for the Nexus 5.
The details of this release come by way of the xda-developers forums and user m3dd0g. The CM11 download, along with the latest Gapps package are both available in that thread, but before anyone heads over to download we will offer the warning -- this appears to be early days for the release. Simply put, there are likely to be some issues and quicks and for that we would suggest not trying this on a phone you consider your daily driver.
Those still looking to move forward will need to now how to begin playing around. You know, the process of rooting your device, making sure your bootloader is unlocked and installing a package such as CWM. There are various how-to pages for those and otherwise, installing CM11 on your Nexus 5 means backing up your current installation then performing a wipe for the data and cache partitions.
From here you install CyanogenMod and then flash the Gapps package. Well, the Gapps package flash is optional, but given it contains the Google services including access to the Play Store, we suspect most will want that installed. That all having been said, the links for CM11 and v4.4 Gapps are included in the xda thread, along with some step-by-step directions that you can follow.