A few years ago I was getting an IFR clearance from ground control. When I called for clearance I had a brain-fart and forgot where we were going. The conversation went like this:

Me: Ground, Lear 1234 looking for clearance to ....... ummmmm .... that airport we're going to.

Ground: Lear 1234 cleared to that airport you're going to via radar vectors...

Don't worry. It came back to me eventually.