We went on 3/22, the Saturday before Easter, this year.
We arrived at just before 11:00 and were seated immediately. I kept an eye on things (to report back here like any good Dis'er would


) They filled up completely at noon and went to taking names at that time.
However, like Crisi mentions above, you can always hit an odd day at an odd time and end up waiting. Generally though if you go close to opening I have never heard of a line to wait at that time.