One way to avoid a presentation disaster is planning ahead for a presentation kit. Nicholas Pyers of AppleUsers.org offers us a look at the cables, adaptors and accessories that any group conducting presentations on regular basis should consider having on hand. By being prepared, you can be sure that if your presenter arrives with the wrong(or no) cable or adapter, the show will go on. Check it out!
http://www.appleusers.org/ugr/presentation-kit/