As I mentioned in reply to haeso’s comment on the first video, there is method of joining rows or columns together called ‘grouping’. It can be very useful when you want to have different ways of displaying data, or be able to collapse certain areas (underlying details, for example).
Here’s a screenshot explaining how you can do this using the menus in Excel 2010:
A shortcut way to group rows or columns is to highlight the rows/columns you wish to group and use ALT+SHIFT+RIGHT ARROW to group the rows/columns, and ALT+SHIFT+LEFT ARROW to ungroup them. You can go multiple levels as well (so you could group rows 1-30, and then group rows 20-25 as a subgroup of the first). The levels are displayed at the top of the red box in haeso’s screenshot and can be clicked to view the entire sheet at any of the levels. Remember: this can be done with both columns and rows (separately).