Sales call for an Indian offshore web development firm

These people keep calling 2 - 3 times a week and wont stop calling. I wish there was a way to block their number.

I literally just got a call from that exact number.  They wanted me to outsource my company to India, where they can provide my services for $10 an hour, to help me cut costs and provide a higher level of service!  Personally I like being able to interact with my clients.  Having people in India, who are a day ahead of us would really create problems for my clients and me specifically.
<begin rant>
This stuff boils me!  I'll be keeping my business needs here in America!  There needs to be a way to get a global "Do Not Call List" setup in which these types of phone calls aren't made!  What a waste of my time!
<end rant>
They had no idea what my business what about or what services I provided.  No clue of my demographics or business model in general.  Good game India!

There actually is a "Global Do Not Call List" (I just googled it).  See www.myprivacy.com