Think about an evening dinner about to unfold. The family has gathered. You're just getting into your chair when the phone rings. Someone is trying to sell you something. Your blood pressure rises. You nearly want to kill. You can stop most of these calls by doing something very simple. On the Internet, type this search phrase: "National Do Not Call Registry." Follow the instructions to place your land line and your cell phone on that list – then, be patient for about 30 days while the registry is being updated and provided to telemarketers.
Understand that not all calls are covered. The law exempts some calls from it. Examples are calls from businesses that you've permitted to call; calls from political groups and charities or for surveys; and calls from companies or businesses with which you have a pre-existing relationship.
After you've registered on the Do Not Call Registry and you still get calls that aren't exempt from the law's protection, what can you do? You can file complaints against the offending telemarketers on the Federal Trade Commission's website and on the Federal Communications Commission's website.
You won't get any money as a result of your complaint, but the FCC or the FTC may impose fines or penalties against them. As hard as it is, take the time to be polite, at least long enough to get the name of the company calling so that you can complain to the FCC or the FTC. Enough people doing this can generate fines against a company so large that it will stop its illegal activities.
Another little point to keep in mind when deciding who to report is whether an automated caller is calling your mobile phone. The FCC's regulations forbid using automated dialing machines to call cell phones. If you get a telemarketing call on your cell phone, there's a high probability that the law has just been broken. Report it to the FCC. Enjoy many quiet dinners.