This house rule is an attempt to use raw, vital Pavlovian conditioning to train the players to show up on time.
The level of the character you generate/play is determined by what time you get your butt in a seat, your dice on the table and pencil to the sheet.
Start at 1:00 PM through to 1:59 PM = 4th level character
Start at 2:00 PM through to 2:59 PM = 3rd level character
Start at 3:00 PM through to 3:59 PM = 2nd level character
Start at 4:00 PM or later = 1st level character
EDIT: Please note that I actually do use this house rule in real life when I DM.