JQ brought this up in a comment about Vegas, but I have to expand a little. Those bastards that are set up at the entryway to most casinos with the people asking "so how long are you folks in town" as you walk by are the worst. They are pimping timeshares, usually, and they lure you in with offers of free shows (alternate greeting - "would you like free tickets to a nice show?"). When you bite, they ask you to attend a multi-hour presentation on buying a timeshare (in the desert? In this economy? Sure, color me stupid).

How to handle these rat bastards:
1) "We're only in town for a few more hours--in fact we're on our way to the airport now."
2) "We're here only through tomorrow morning, but soon we'll be back to our new timeshare!" Act glazed eyed and happy when the person says "congratulations!"
3) "No espeaked de English" and keep walking.
4) "I would love a show, but first I need to ask if you've accepted Christ as your personal savior?"
5) "Eye don't thing we have time as we are meetinga friends" in a Pakastani accent (very confusing as those of you who have met me know if I was any more white I'd be clear).
6) Take of your shoe and beat the crap out of the salesperson, as they surely deserve it.