I was near the HAMLET box office at noon today and the line outside was insane. I'd say get there early if you want to make sure you get a rush ticket.
I wanted to get a rush ticket for MEMPHIS for the 7pm performance, but they were only offering rush for the matinee...weird.
I rushed Hamlet for a Friday evening during their 2nd week of previews...I don't know if it's changed since then but I got there at about 9 AM and there were only 2 people in front of me and a lot of empty seats in the rush section.
The other day my friend and I were walking past the theater and two people stopped us and asked if we would get them a student ticket (one was a student) and we went right in and got them, it was like row G on the aisle in the Mezz.