So much misinformation in this thread...
1. You do not have to use the exact words of "Place me on your do-not-call list". You simply have to let them know that you do not want that particular company to make an unsolicited telemarketing call to you at that number again. If they call you back again, you can sue them in small claims for a maximum of $500 plus court costs for each occurrence after the first call where you told them not to call you back.
2. Within 30 seconds of your answering the phone, the telemarketer must identify themselves, the company they are calling for, and the nature of their call. If they don't do that, you can sue them in small claims for a maximum of $500 plus court costs for each occurrence.
3. If you sign up for the National Do Not Call list, your realtor won't be able to call you, your friend won't be able to refer you to that insurance agent or mortgage broker who just gave him a great deal, etc. Because NO ONE (except political organizations, who are exempt) will be able to call you for anything even remotely related to a sales call UNLESS you initiated the process by calling them first within the last 90 days or you have had a prior completed sale to them in the last 18 months. Otherwise, they can't call you even once, not even a hit on your answering machine or even your caller ID. And that's not just telemarketers, that's everyone -- realtors, lawyers, insurance agents, bankers, brokers, loan officers... EVERYONE.
4. If you are signed up for the National Do Not Call list and someone does make some type of sales call to you as mentioned in #3, you CANNOT sue them for any dollar amount, unless they violate 1 & 2 above (and those are different, prior laws). The best that will happen is that the government will fine them a maximum of $11,000 and you won't get one penny.
SunnyD, it sounds like the person who called you was in violation of 1 & 2 above. If they do call you in 3 days, you can sue them for $500. It's so easy to that there have been reports of some people making a living at it.
edit: work #'s, business #'s, and any phone # used for commercial purposes are exempt from all of the above.