gistfile1.js

var events = require('events'), sys = require('sys');

var emitter = new events.EventEmitter();

function fn1() {
    sys.debug("in fn1");
    emitter.addListener("foo", fn2);
    process.nextTick(function() {
      emitter.removeListener("foo", fn1);
    });
}

function fn2() {
    sys.debug("in fn2");
    process.nextTick(function() {
      emitter.removeListener("foo", fn2);
    });
}

emitter.addListener("foo", fn1);

emitter.emit("foo");
emitter.emit("foo");

// outputs fn1, fn2, fn1, fn2, fn2