If you are a user of Google Forms, then you might want to check out another great Add-On called Form Scheduler. The free version gives you the chance to close your Form at a maximum number of responses or a specific date.
There is a paid feature to open your form during specific events. For example, let's say that you have a reoccurring event that happens from 9 am to 1 pm on your Google Calendar. You can use Form Scheduler to open during that time period.