Voters can register as Democrats the day of the caucus. (Republicans have to be registered as Republicans at least 30 days before the caucus date.)

The county to watch, of course, is Clark County (home to Las Vegas) with more than 600,000 active (and 800,000 total) registered voters. The next biggest county is Washoe (home to Reno) with over 200,000 active voters. After those two, there's a huge drop-off in active registered voters for the other counties. A few have 20,000 to 25,000 voters and many more have 2,000 - 3,000. Clark is substantially more Democratic, Washoe is slightly more Republican.

And, some good news: Most ex-offenders can vote in Nevada -- their right is automatically restored:

If a particular individual was released or discharged from prison, parole or probation on or before July 1, 2003, his/her right to vote was automatically restored by operation of law as of the date of such discharge, with no conditions related to the nature of the conviction.

If a particular person is released or discharged from prison, parole or probation after July 1, 2003, unless his conviction is specified in NRS 213.155 and 213.157 as excluding him from the automatic restoration of voting rights, his/her right to vote is automatically restored by operation of law as of the date of such discharge.

Registration opens at 11:00 am PT. The Democrats should start phoning in results around 12 to 1:00 pm PT. Caucuses end at 1:00 pm. (Note that the Republicans start and end two hours earlier.)