How do you guys handle holidays?

It is not a best practice whatsoever and I'm not sure if it will work, but you can try modifying your wait step to a certain date, like next Tuesday. I myself would let this one go, but when you create another Nurture Campaign try to avoid those dates in your planning phase. The ability to choose dates to wait til makes this process a lot easier than in the past. We were tired of counting days. 

What I am not certain about is how the Leads will react if you modify a flow step that they currently reside in, but if you modify any future flow steps the campaign should continue without a hitch. Just like switching an email out, modifying the Wait step should have no affect. 

I'm hoping that the new Engagement Module will support blackout dates.

I think we underestimate client's consumption of materials on off-peak days. Sometimes the quiet moments while sitting by the pool are the time you can get the greatest exposure of your materials. I wouldn't do anything but let the campaign run.

Adam, as a B2B business, our web page visits on holdiays and weekends are less than 20% of our visits during the week.  Maybe we would get more traffic if we sent them an email on weekends and holidays ;0)  Certainly worth testing.