Hiding and Unhiding Rows

I missed the Unhide Macro
Sub UnhideRC()
With ActiveSheet
.Rows.Hidden = False
.Columns.Hidden = False
End With
[a1].Select
End Sub

Interest Comments by all.
Starting from the top.
Alex B. I managed to hide all the rows, not woken properly, so needed a macro to unhide them.
Charles Pegman, You can also set the Column width to 0.5 (Excel changes it to 0.43) and you will hardly notice. However, I would hide the column and unhide it in the macro before running the code and then rehiding it at the end. (See Test code)
Tamara Powel; Neat idea! I hadn't thought of that.

Sub WorkWithHidden()
Dim rg As Range, c As Range, lrow As Long
With Application
.ScreenUpdating = False
End With
UnhideRC
'test code
lrow = Cells(Rows.Count, "C").End(xlUp).Row
Set rg = Range(Cells(1, 3), Cells(lrow, "C"))
For Each c In rg
Debug.Print c
Next
[C:C].Columns.Hidden = True
End Sub

The instructions to hide / unhide rows also applies to columns.

The tip should work for unhiding the first row or column in a table unless its also the first row or column in the spreadsheet.

In Excel 2010, what works for me if Row 1 is hidden is to hover over the top left corner (the select all corner) and then lower you cursor until you get to the bottom margin of that square at which point the cursor changes to a double line with arrows in both directions. Double click and it will unhide the row.
This works for columns as well but you would move to the right hand side of that box for the cursor to change. I do find you need to need to scroll the sheet left to show the now unhidden first column.
The cursor change doesn't happen if there is nothing hidden in the direction you are trying to unhide.

You can also do <F5> a1 OK and then unhide but the above is easier. (ie Goto the hidden cell a1)

HIDING OF COLUMNS
I have a worksheet where I use a macro to copy data from a "booking" sheet to an "invoice" sheet.
I hid some columns on the booking sheet to make things clearer and the invoices stopped working properly. After investigation it turns out that columns with width=0 are ignored by the macro, so all the subsequent cells are in the wrong place (by the number of cols hidden).
My fix is, rather than use "hide", I reset the width to 1 pixel. Not as neat on the screen but saves having to recode the macro.

If the first row is hidden, you can click the triangle in the top left corner to select the whole sheet, then right click on the row numbers and select unhide.

I'm with Alex though, I almost never hide rows or columns, I just group them so that they won't show. If I need hidden areas for formulas or lookup tables (for data validation drop down lists for example) I just put them all in named ranges on a new sheet. If it needs to be hidden then I can hide the whole sheet and not copy something over a hidden field by mistake.

The easiest way to hide a row is to highlight the row or rows, right click, and select hide. To unhide, highlight the visible rows on both sides of the hidden, right click and select unhide.

This method does not work for unhiding the first row or column in a table.

Its worth considering using Data > Group to hide the rows because that gives you a visual queue that you have rows hidden, as well as a toggle switch to hide and unhide the rows.