In addition to these suggested "Note" options you can also download a Lightroom Plugin called "Johns Big Note" which gives you a field into which you can type a reasonably large text item to assist in providing you with more information.
DWU2 wrote:
If you use Lightroom, you can enter keyword tags, location information, title, caption (or large caption), and labels. In addition you can provide location information, and, if your camera is so equipped, it will automatically capture GPS. It will also automatically capture time and date.
But, none of that will help you if you don't document the event after you get home with the pictures.