When you create column guides in either the New Document or Margins and Columns dialogs, InDesign evenly distributes the columns between the left and right or inside and outside margins, resulting in symmetrical columns. If you don’t want symmetrical columns, for example if you want a wide inner column and narrow outer column, are you stuck faking it using ruler guides? No.
Like ruler guides, column guides, once added to the page, can be unlocked and moved. They’re locked by default, but a quick trip to View > Grids & Guides > Lock Column Guides cures that. Once unlocked, click and drag a column guide to move it and it’s mate across the column gutter (InDesign preserves the gutter width). Unlike ruler guides, however, column guides cannot be precisely positioned using the Control or Transform palettes. Thus, you’ll need either a good eye or a ruler guide waiting to serve as a marker.