For this game, hide some of the stuff of the child who is leaving, such as his/her 'favorite shoes', 'favorite book', 'beloved T-shirt', 'prized toy', etc. at various places. Next, make teams of the kids and give each of them a list which consists of all these items. The teams now have to get hold of as many items as they can from this list in ten minutes. The team which brings back the maximum number of items is declared the winner and is given a prize in the end.
One of the most interesting games is to keep a quiz on the life of the person who is going away. Divide all the guests into teams and ask them questions such as "In which year did John pass out of college?" or "Which is John's favorite movie?" or "How many girls has John dated seriously in his life?" etc. Such a quizzes can be a lot of fun when there are close friends present who know the person inside out. You can also have a similar trivia quiz about other topics.