The Clark County Marriage Bureau is great. We came here to get our Marriage License. They are open from 8am - 12pm midnight, daily. Fill out your form online here https://aivitals.co.clark.nv.us/webinquiryinternet/ and click on the Marriage Application tab. Keep your confirmation number, and just walk right in. It literally took 5 minutes to get the license from the time we walked in the door till we left. The license is $60, and then an additional $15 when you order the certified copy through the mail for Social Security, DMV, etc. It was the most painless process ever.
I would recommend going in during the week in the late evening. There was no one there at 9pm on a Thursday. Also, bring cash, or they will charge you $5 for the credit card transaction. Im cheap. I hate fees.