If you want to make your event an experience, not just an event, check out The Art of Experience Design from Digital Digressions (with a tagline like, "A testament to the need to play, experiment, and stay curious," I couldn't resist this one). The writer points to seven things you have to do to make something really engaging and, well, an experience (paraphrased by me for the most part. Go read the original to get all the details.)
1. Don't just amuse the masses—engage the individual.
2. Stimulate all the senses.
3. Make sure everything, from the service levels to the lighting to, well, everything, works together to build the experience you want them to have, and doesn't distract them from that experience. We've all dealt with this, such as a room that's so cold that everyone's shivering instead of engaged in what's going on. As the writer says, "The easiest experience to create or have, is a bad one."
4. Make it personal for each individual who attends, as much as is humanly possible.
5. What makes your event worth the price of admission? Concentrate your efforts in these areas.
6. I really like this one: Instead of just leading people to expect a free pillow gift, or discounts on next year's event, surprise them after the fact. Give them something that shows how much you appreciate they're coming to the meeting, something they don't expect to get. The examples the writer uses are, "surprise payments after a car purchase to congratulate the customer on his choice, or recognising a frequent customer and giving them the purchase on the house - these are all events that create positive surprises, memories and add an element of suspense: What will happen next time?"
7. Don't rely on the same old, same old. "With surprises: they need to remain unpredictable and new every time, same with any experience: something has to continuously evolve to make you want to have the experience over and over again," the writer says.
Great advice, even if it's not always easy to follow through on.