Can I have the times on the SignUp display as Military Time or as a 24 hour clock?

On each SignUp, you can choose to change the time format from a 12-hour clock to Military/24 hour time. The SignUp Organizer can turn this option on or off in the first planning step (Provide Details), and later in the Details tab of your SignUp's Organizer view: 

Start by going to the Details tab of your SignUp's Organizer view. (Login and in the My SignUps menu on your Dashboard, click the SignUp Title to open your Organizer view). 

Scroll down and check the box Use 24 hour time format, then click the blue Update button at the top or bottom of the page to save your selection.