Click and hold down with your cursor on the Calendar in your Dock. You get 3 choices: Quit, Hide, Options. Options gives you the choice to Open at Login. This is a handy way to quickly view the month each morning when you turn the computer on. It’s a reminder about all those family birthdays you’ve entered, along with SIGs upcoming from Bobbie Pastor and John Carter. (You did update the Calendar, didn't you?)