"air duct cleaning".  what is it with these pests?  i have asked politely to never be called again (which they ignore), hung up on them, left their calls unanswered, etc. but they keep calling back.  if i have the time, i give them minimal encouragement (a few grunts), and let them run through their script (if they want to waste my time, i will waste theirs), before cutting them off.

obviously, they aren't getting any legitimate business from these calls, so why are they calling?  are they selling my number on to other telemarketing pests, as "verified", or are they casing my place for break-ins or whatever?

failure to properly identify yourself over telecommunications (and i would classify bogus callerid as such) is a criminal offence, and i wish the police would do their duty and prosecute them.