What are the roles and responsibilities of each office within a
generic committee?  In other words, what does a president, secretary,
etc. generally do within a given committee?

The three primary roles in any committee are:

1. Chairman
This person chairs all meetings of the committee and acts as a
figurehead for the group.

2. Secretary
This person will take minutes of meetings and handle all
correspondence for the committee.

3. Treasurer
They will handle accounts for the group and keep control of financial
business.  They should approve all expenditure and handle all income
for the committee.

These roles can be split, for example having a 'correspondence
secretary' and 'minutes secretary'.  Depending on the group, there may
be specific roles such as 'Fundraising Officer' or section officers. 
There is also usually a vice chairman to chair meetings or represent
the group when the chairman is absent.

The rest of the committee may have titles if they handle specific
parts of the group, or they may simply be there to make up numbers and
aid decisions.

Hope this helps,

Gremmy

I should add that a chairman can also be female, and is sometimes
referred to as a 'Chairperson' or more simply, 'The Chair.'

There can also be honorary positions, which are awarded to members who
have contributed in the past but no longer want real responsibilities
in the committee.

Occasionally, a group might also have a president.  In this case, they
will do most of the 'figurehead' appearances instead of the chairman.