Hi Larry,
You can enter the Date using the Insert > Date and Time menu item, or by pressing shift-option-command-D.
If you also want the current time included in the entry, do the above, then double-click the cell to open the set date dialogue and choose the last format in the popup menu.
OR:
Enter the formula =TODAY() in all cells (after the last date you've entered) in the Date column. As each day arrives, select the cell(s) for that day, Copy, then Edit > Paste Values.
OR
If you're using a single row for each day's entries (ie. morning and afternoon levels recorded in separate columns):
Enter the starting date into a Header row. (example uses cell B1)
Enter the formula =B1+1 into B2 (row 2 is the first non-header row)
Fill the formula down to the rest of the cells in column B.
To add dates, drag the Row handle down to add rows. The formula will automatically fill into the new rows (IF every regular cell in the column contains the formula).
In any of these you can format the cells to show the date in a format that includes the weekday name.
Regards,
Barry