Ctl + Semicolon inserts the current date in a field (at least on my PC). Ctl + Shift + Colon (which is the only way to get the Colon) inserts the current Time, Ctl + apostrophe copies the value from the current field in the previous record to the current field in the current record, and Ctl + Shift + Quotation Marks seems to do the same thing as Ctl + apostrophe.
HTH
Paul