def timezone_choice(tzname, country=None):
    """
    Given a timezone string, convert it to a two-tuple suitable
    for a choice in a FormField.

    >>> timezone_choice('UTC')
    ('UTC', 'UTC')
    >>> timezone_choice('Australia/Sydney')
    ('Australia/Sydney', 'Sydney')
    >>> timezone_choice('America/Indiana/Indianapolis')
    ('America/Indiana/Indianapolis', 'Indianapolis (Indiana)')
    """
    try:
        base, rest = tzname.split('/', 1)
    except ValueError:
        base, rest = None, tzname
    rest = rest.replace('_', ' ')
    try:
        mid, rest = rest.split('/')
        if mid != base and mid != country:
            rest = '{0} ({1})'.format(rest, mid)
    except ValueError:
        pass
    return (tzname, rest)