Unhide multiple sheets

If it's something you want to do over and over (hiding and unhiding) then you can creat two (or more) custom views.
Set up the file with everything hidden and goto view>custom views. Name this view "PresentationView" for example.
Then do the same with everything unhidden and name it "AllSheetsView" for example.

This still involves the manual task of hiding/unhiding one by one but once you've done it once for each view it will save you time in future.