When you are entering dates in an Excel spreadsheet, you might want to enter just the numeric part (i.e. without any dashes or slashes), hoping Excel would figure out what you were doing and turn it into a 'real' date automatically.  You might think Excel has a built-in cell format you can apply that would handle this for you...it apparently does not. 

You can, however, build your own 'custom formatting' rule for a cell to accomplish this.  So, for example, if you want to type in '112507' but have Excel transform that into '11/25/07', you would set up your custom format (using Excel 2003) like this:

1. Right click the cell, choose 'Format Cells...'
2. In the 'Category' list (on the left side), scroll down and click on 'Custom'
3. In the 'Type' textbox, type in your new rule (in this case '0#"/"##"/"##', with out the single quotes)

Now, when you type in that cell, your date will be reformatted according to your new rule. 

To apply this custom format to an entire column of cells: 

1. Right-click your custom-formatted cell, then click Copy.
2. Highlight the cells you want to apply the format to, then right-click one of them
3. Choose 'Paste Special' from the context menu
4. Click 'Formats' from the 'Paste' group