Help me with english "phone bank" "roll calls for" "sell Kool-Aid for"?

> "punching in numbers at the phone bank"
"Punching in numbers" refers to dialing telephone numbers (using a key pad, so the action is thought of as "punching" in the numbers). For purposes of fund raising or urging voters to vote for a particular candidate, the volunteer phone callers have to make many many calls. To this end, in pre-computer days they were supplied with long lists of phone numbers -- most of which came to nothing. Either the number was defunct, or no one answered, or the line was busy, or the person hung up. Only a few people would stay on the line long enough to hear the message (called "the rap"), and only a few of those would send money. So the callers worked through a LOT of numbers.
Now the dialing is done by computer. The computer dials random numbers and feeds the call to a volunteer only if a human voice says "Hello?" That's why -- if you are receiving one of these calls -- there's a little pause before anyone speaks to you, and you say "Hello" twice.
http://www.ehow.com/how_2083797_use-camp...

> "Phone bank"
A phone bank is a room set up to make or receive phone calls. It has a ton of phones, all in use at the same time. They are sometimes called "call centers."
You can see phone banks during televised fund-raising events; the volunteers who man the phones are often featured. ("Our phone bank tonight is staffed by volunteers from the John Hancock Insurance Company, and we thank them very much for their time." (Camera scans them; they wave awkwardly and grin.) "So please call now and make a pledge to donate to (this good cause.) The volunteers from the John Hancock Insurance Company are ready and waiting -- so make their phones in the phone bank ring!")
A phone bank might also be set up for customer service, tech support, taking orders, etc.
The winner in "Slum Dog Millionaire" found his long-lost brother by using the Directory Assistance capability of the phone bank he worked at.
Phone banks set up for outgoing calls are also called "boiler rooms." These make thousands of calls per day, selling products or raising money, polling, etc.
http://en.wikipedia.org/wiki/Call_centre

In this case, the word "bank" does not refer to a financial institution. Instead, it suggests its meaning of "a piled-up heap or mass" -- especially one around a periphery (such as a snow bank) -- because of the way the room is ringed with calling stations against the walls.
http://www.thefreedictionary.com/bank

> "rolling calls" is jargon, but it evidently means "working through the list of phone numbers."

So the entire passage says that he volunteered at a call center ("phone bank"), dialing ("punching in") phone numbers, making call after call ("rolling numbers"). If someone answered, he read them his rap (his scripted spiel, his speech, his appeal) and got them to (whatever -- send money, promise to vote, agree to a lawn sign at their house, etc)
http://en.wikipedia.org/wiki/Lawn_sign
~~~~~~~~~~~~~~
Q3) Selling Kool-Aid
This is some kind of jargon specific to this political activity. I don't know exactly what it means. It's a metaphor of some sort, referring to raising money. Money is not raised for political candidates by literally selling things.

"Selling Kool-Aid" refers to this popular way for kids to raise money for some good cause
http://www.houmatoday.com/article/20100119/ARTICLES/100119315
Well-wishing adults buy a warm cupful (of dubious cleanliness) and hand over a dollar.
I did it myself when I was a kid -- except that (before we even reached our selling location) our big jar of Kool-Aid shattered when it fell out of the little red wagon we were lugging it in. LOL!

In this case, the phrase is apparently being used as a metaphor for fund-raising.
The tone is slightly mocking or disparaging -- almost a suggestion of a "hustle."