Facebook – How to unhide a friend on your Facebook wall

There is a greasemonkey script for blocking all pending invitations you currently have but there is obviously no way to block all applications in facebook with one click - this would pretty much destroy the whole business model of facebook.

It shouldn't be too stressful to block the apps as they come - I did this for one week and now it happens VERY VERY rarely that I ever see a new app on my wall. There are 5 to 10 annoying apps that are wide spread - once you blocked them it should be very quiet on your wall.

It sounds like the event has been deleted. What's the time frame between hiding the event and trying to view it?

Facebook might also have locked you out of viewing the event, depending on its privacy settings. You could have removed it from "My events" instead of hiding it, by accident.

The event is probably not public, judging from its behavior.

Events have two different privacy options depending on how the admin set up the event:

1. Public Events: Anyone can add themselves to the guest list without receiving an invitation or being approved by an admin. They can see the event information and all associated content (e.g., photos, Wall posts and videos).
2. Private Events: The event cannot be found in searches. These events are by invitation only. People who have not been invited cannot view the event description, Wall, or photos. They also will not see any Feed stories about the event.

— Facebook's Help Center (emphasis mine)

I think the only thing you can do is ask the creator to invite you again.