Is there a way to unhide multiple sheets at the same time in Excel?

If you are able to have macros in your workbook I would go for this option...

You need the first block of code found here. I just tested in Excel 2007 and it works.

In 2007, go to the View tab and find the Custom Views button. Unhide all the sheets in your workbook and add a custom view called "ShowAll". Then hide the sheets you want and create another custom view called "HideSome". Now you can quickly hide and show those multiple sheets by selecting a custom view. Of course you'll want to name your custom views better than my example.

In 2003 and earlier, it's under the View menu.