- Vampires - They are so hot right now. You can add vampires to anything and people will come running. Heck, that's why I'm planning to open a vampire-themed oil change place named Dracu-Lube. "We want to give you and your car eternal life." So, you put vampires at the Renaissance Fair. The princess drops her handkerchief to the winning jouster, a vampire comes in and bites her neck. The jouster vows revenge to the king. It's glorious.
- "Green" It Up - Make the suits of armor out of solar panels. Hook the horses up to a power generator like they do with bicycles. Have the jousters "horse-pool." Put two jousters on one horse and get two jousts done at a time. Go paperless. Scrolls have to be the largest contributer to a Renaissance Fair's carbon footprint. They love them. Have the decreers memorize what would have been on the scrolls. Simples as that. A green Renaissance Fair is far more marketable than the alternative one.
- Reality Series - Get a cable network to televise Renaissance Fairs around the country. People will come just to get the chance to be on television. You can even do period-based segments like Cash Carriage or Mace Men. This should be good for at least a season.
- Technological Renaissance - There are different ways to interpret a renaissance. Some say we are in the midst of a technological renaissance. Why not go with that? Robo-Knights sound much cooler than regular knights. Instead of plain swords, you get laser swords. When people question the stupidity of a laser sword, tell them their archaic minds could not comprehend the science and to just try and follow along. Finish the Fair off with a Robo-Knight malfunction where the robot sparks and frightens the people back to the cars.
I don't know if you can do all of these things at once. We all know that vampires hate laser swords so you'd have to keep those separate. Regardless, I give any of these the Tor's Take Guarantee of Success.* Good luck to you, Renaissance Fair or should I say, Renaissance Awesome!
*Excludes Vermont, Montana, and Southeast Wyoming.