Definition: A "nightly" is a bleeding edge release that is built on a daily basis, usually at night after a full day's worth of new code has been committed.

It could oftentimes be unstable and not properly tested, lacking any changelogs, but eventually evolving into alphas, betas, release candidates, and finally stable releases.

After rolling out CyanogenMod 10.1 nightly builds for three other devices yesterday (along with M2 builds), the CM dev community has kept the steam going into today - adding 7 new supported handsets to the latest version of Android's most popular custom ROM.

bionic

d3

d4

hox

kf1

kf2

razr

Here they are:

In addition, the Optimus L7 received its first official CyanogenMod build, though it's only version 10 (Android 4.1), and can be found here.