Claiming to be a firemens fund selling tickets to a benefit concert. They will NOT take a pleasant no for an answer. If you let them engage you in conversation and you still say no, they will hang up on you. They are intruding on your day uninvited, so if they can't train their reps to be civil, don't even answer 901-969-2460.
Charities and political affiliations are exempt from the "DO NOT CALL" registrations. They also will often gather the information from voter registration records. Call blocking would be the only way to stop getting the annoying call from them. The Federation of Police do the same telemarketing for funds. If you have told them not to call you, a law suit might be in order.