OFFSET($A$1,ROW()-1,COLUMN()-1) : the 'current' cell (never use it, would probably cause a circular reference)
OFFSET($A$1,ROW()-1,COLUMN()-2) : the cell to the left of the 'current' cell
OFFSET($A$1,ROW()-1,COLUMN()-3) : the cell two columns to the left of the 'current' cell
 OFFSET($A$1,ROW()-1,COLUMN())   : the cell to the right of the 'current' cell
OFFSET($A$1,ROW()-1,COLUMN()+1) : the cell two columns to the right of the 'current' cell
OFFSET($A$1,ROW(),COLUMN()-1)   : the cell beneath the 'current' cell
OFFSET($A$1,ROW()-2,COLUMN()-1) : the cell above the 'current' cell

OFFSET(reference, rows, cols, [height], [width]) 
 
The OFFSET function syntax has the following arguments:
 
Reference  Required. The reference from which you want to base the offset. Reference must refer to a cell or range of adjacent cells; otherwise, OFFSET returns the #VALUE! error value.
Rows       Required. The number of rows, up or down, that you want the upper-left cell to refer to. Using 5 as the rows argument specifies that the upper-left cell in the reference is five rows below reference. Rows can be positive (which means below the starting reference) or negative (which means above the starting reference).
Cols       Required. The number of columns, to the left or right, that you want the upper-left cell of the result to refer to. Using 5 as the cols argument specifies that the upper-left cell in the reference is five columns to the right of reference. Cols can be positive (which means to the right of the starting reference) or negative (which means to the left of the starting reference).
Height     Optional. The height, in number of rows, that you want the returned reference to be. Height must be a positive number.
Width      Optional. The width, in number of columns, that you want the returned reference to be. Width must be a positive number.
 
Remarks
If rows and cols offset reference over the edge of the worksheet, OFFSET returns the #REF! error value.
If height or width is omitted, it is assumed to be the same height or width as reference.
OFFSET doesn't actually move any cells or change the selection; it just returns a reference. OFFSET can be used with any function expecting a reference argument. For example, the formula SUM(OFFSET(C2,1,2,3,1)) calculates the total value of a 3-row by 1-column range that is 1 row below and 2 columns to the right of cell C2.