I use Aperture for organizing my photos but this tip would apply to Lightroom, iPhoto or any other photo organizer. Whenever I go to a music festival the schedule is usually available as a PDF from the promoters web site… copy that into the project so you’ll have a reminder of what shows were there. Same idea would work for any event that has printed materials that would help your memories later, scan them when you get home or take a photo of them.