This script was written as the answer to a StackOverflow question about forwarding emails to a rotating list of people. See http://stackoverflow.com/a/15984468/1677912.

ForwardHuntGroup.js

/**
 * Retrieves a given user label by name and forwards unread messages
 * associated with that that label to a member of the Hunt Group.
 */
function huntGroupForward() {
  // get the label for given name
  var labelName = "elephant"
  var label = GmailApp.getUserLabelByName(labelName);
  if (label == null) throw new Error("No messages for label "+labelName);
  // get count of all threads in the given label
  var threadCount = label.getUnreadCount();
  if (threadCount == 0) return;  // quick exit if nothing to do.
  var threads = label.getThreads();
  var messages = [];
  for (var i in threads) {
    if (threads[i].isUnread()) {
      messages = messages.concat( threads[i].getMessages() );
    }
  }
  for (var i = 0; i < messages.length; i++) {
    if (messages[i].isUnread()) {
      messages[i].forward(nextHuntGroupMember());
      messages[i].markRead();
    }
  }
};

/*
 * Global object to store working copy of the Hunt Group
 */
var huntGroup = { next : 0, members : [] };

/*
 * Get the email address of the next Hunt Group Member
 * to forward a message to.
 */
function nextHuntGroupMember() {
  if (huntGroup.members.length == 0) {
    // Load members
    var sheet = SpreadsheetApp.getActiveSheet();
    var data = sheet.getDataRange().getValues();
    for (var i = 0; i < data.length; i++) {
      huntGroup.members.push(data[i][0])
    }
    // Make sure we have members
    if (huntGroup.members.length == 0) {
      throw new Error("Found no email addresses");
    }
  }
    
  // Retrieve next index. Properties are always stored as strings, so
  // we need to parse the retrieved value to use it as a Number.
  var next = parseInt(ScriptProperties.getProperty("nextHuntGroupMember"));
  if (next != null) {
    huntGroup.next = next;
  }
  else {
    next = 0;
  }

  // get next member to be used
  var nextMember = huntGroup.members[next];
  // ... then move on to new next (increment modulo list length)
  next = ++next % huntGroup.members.length;
  // store the new next value
  ScriptProperties.setProperty("nextHuntGroupMember", next);
  
  return nextMember;  
}