Some going away party ideas include holding a luau or an "adios amigos" party. Both of these incorporate the going away theme and impress guests of all ages.
For a luau, decorate the venue with Hawaiian-themed supplies such as grass skirts and leis. Hosts can also serve fruits and cocktails that fit in with the tropical theme.
For "adios amigos" parties, decorate with Mexican-themed items such as sombreros and pinatas. One great idea is for the guests to fill a pinata with cash to help the guest of honor with his or her trip. Chips and salsa make good appetizers for this type of party.