Last year my sister and I threw a large party for our mother's 90th birthday party. We had to have it (as a luncheon) in a hotel as there were 130 guests. This included relatives, friends, former employees or co-workers and even her hairdresser. Mom had to be involved to set up the seating chart as she was the only person who knew everyone.
We discouraged physical gifts, as she has been ridding herself of clutter over the last few years. However, a lot of people got up to speak about how she had affected their lives. She really liked that, and it helped to show people facets of her they did not know.
Actually, she had a gift for everyone who attended. Over a span of about six months my brother-in-law (who was in Public Relations) and one of his son's (who is a newspaper editor) conducted and recorded interviews with her for several hours once a week, and the following week would give her kind of a transcript. This was made into a paperback book of almost 200 pages and John had about 150 printed up for distribution.