The first CyanogenMod 10.1 nightly builds are starting to trickle down for Google's ultra high-res Nexus 10
tablet. Those of you who snatched the $399 slate, and would like to mix it up a little with a streamlined and modified Jelly Bean 4.2
version, CM 10.1 is your best bet.
The nightlies have a couple of bugs in them, as is typical for initial releases, and the download will run you abut 164 MB at last check. You can download the files from the get.cm repository in the source link below and give it a modding shot.
If you want to root your device, and prep it for these custom ROMs like CM 10.1 that are coming your way, check out its toolkit here