As an intern a lot of the duties are pretty much the things the staffer's don't want to do themselves or don't have time to do themselves.
Examples:
Answering the phone, staffers can't spend all day on the phone talking to people or they wouldn't be able to get their jobs done. Their jobs consist a lot of doing research for bills, understanding bills, and answering mail. Staffers have certain subjects that they specifically are in charge of understanding and helping the Congressman in understanding and getting the work done for that area.
Interns sort through mail, every office has their own process. The office I work in we sort it into the subjects for the staffers, the staffers then decide what the response is. Also we help to get the mail ready, entering information into the computer, helping draft in some cases.
Typical intern job running errands; it's really not that bad. I enjoy doing the errands often times because it gives me a chance to get out of the office and to do a little bit of exploring or simply stretching my legs for a few minutes.
One of my favorite duties is giving tours. I was terrified at first thinking of having to give a tour, but really it's not that bad. You learn the facts as you go through the tour more, whether running through it in your head or actually walking through it. Plus you get to meet and talk to the people who are here to visit. Plus going through the capitol is amazing. It's so beautiful and has so much history.