When setting up an event you have the option of setting an End Date in the Event Information section that displays the number of Days Left to Give on participant pages. There is also an option to display the Days Left to Give in the thermometer that is set in Website features. Do either of these affect donors ability to donate to the site after the date has passed?
No, these dates only serve as a reminder and will not disable the sites ability to accept donations. You must disable the event in order to disable donations.