This was the same charity premiere event as the Mark Hamill and Billy Dee Williams encounters. We had been working the party for most of the evening when I spotted a small child. They were few and far between at this event, so I paid more attention and got down on his level to interact with him for a few minutes. When we were done playing and taking photos, his grandfather (I assume) thanked me for being so nice. Lo and behold- it was Doc Brown himself! Hoping he would remember me, we found him again later in the evening and this time we had our own camera!