A few days ago, T-Mobile's version of the Samsung Galaxy S II, codenamed "Hercules," received a hearty scoop of Ice Cream Sandwich. Today, the fun continues for owners of the device, as Team Douche just made available official CM9 nightlies.
Definition: A "nightly" is a cutting-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.
Additionally, those in possession of AT&T's Galaxy S II Skyrocket (a device that has not yet been dealt an official dose of ICS) can rejoice as well - CM9 nightlies are now out for this handset too.