Public Speaking: Get Them In Fun
If you want your audience to laugh, they must be in fun. You, the speaker, must be in fun. The emcee or program coordinator must be in fun. The whole program should be designed in fun. Don't do anything to take them out of in fun. Don't speak about controversial subjects like religion or politics and don't make unfriendly comments to audience members. If a problem occurs which must be dealt with, find an in fun way of doing so.