For multi-select boxes where you have a list of things you want to filter on, and you want the queryset returned to be an OR'd set.

    qset = Q(mode__exact=modes[0])
    if len(modes) > 1:
        for mode in modes[1:]:
           qset = qset | Q(mode__exact=mode)
    r = Responses.objects.filter(qset)

Now, I need to figure out how to do this as a list comprehension!

For extra coolness, you can see what SQL you're generating:

    print r.query.as_sql()