Perl, 99 81 75 bytes
{($s,$n,$h)=localtime(time);printf"%02d:%02d:%02d\n",$h,$m,$s;sleep 1;redo}
while(1){my($s,$n,$h)=localtime(time);printf"%02d:%02d:%02d\n",$h,$m,$s;sleep(1)}
while(1){my($s,$n,$h,$x,$x,$x,$x,$x,$x)=localtime(time);printf"%02d:%02d:%02d\n",$h,$m,$s;sleep(1)}