Frank,
I use the following methods on my timesheet workbook. To fill in the next empty cell with the timestep you need to determine the "active" cell. I do this in two steps using excel formulas because I don't know enough VB to accomplish the equivalent in code. Then I use a vb macro to stamp the value.
1. Find the active cell.
Say that the list of elapsed times is in column a rows 2 to 20.
In an unused column, say column D,
let D1 = the number of values in the list = count(a2:a20)
The address of the first open cell in the list is:
=CELL("address",OFFSET(a2,D1,0))
2. Stamp the time (or any other value you want) into the active cell using the following macro, which you may want to assign to a button on the worksheet (I like to use textboxes so they are easy to label, then right click>assign macro):
Sub stamp_active()
'
' Stamps time into active "end time" cell
' Macro 5/11/2004 by Brian Taylor
'
'
mystamp = Time
' Note - "d2" below matches the example. This is the cell that has the address of the active cell.
Range("d2").Select
activecelladdress = ActiveCell.Value
Range(activecelladdress).Select
Selection.Formula = mystamp
End Sub