I don't know if this would be considered an obfuscation or a golfing exercise, but nonetheless, in only 451 characters, I present you with John Conway's Game Of Life.

my($a,$c,$g,@b)=(40,10);$\=$/;for my$r(0..$a){$b
[$r][$_]=!int(rand($c))?'*':$"for(0..$a)}sub g{
my($d,@e);for my$r(0..$a){for(0..$a){my$h=0;for
my$i(-1..1){for my$j(-1..1){my($f,$g)=($r+$i,$_
+$j);next if$f<0||$f>$a||$g<0||$g>$a||!($i||$j);
$h++if$b[$f][$g]ne$"}}$e[$r][$_]=($b[$r][$_]ne$"
&&$h==2)||$h==3?'*':$";$d++if$e[$r][$_]ne$b[$r][
$_]}}@b=@e;$d}do{print`clear`,++$g;for my$r(0..
$a){print map{$b[$r][$_]} (0..$a)}select $&,$&,
$&,.4}while(&g)
[download]

Update - Using a few tricks I picked up from teamster_jr's wonderful version below (and a few golf tricks I always seem to forget to implement, I knocked it down to 366 characters.

$a=40;$\=$/;@a=0..$a;for$r(@a){$b[$r][$_]
=!int rand 10?0:$"for@a}sub g{my($d,@e);
for$r(@a){for(@a){$h=0;for$i(-1..1){for$j
(-1..1){$f=$r+$i;$k=$_+$j;$h++if$b[$f][$k
]ne$"&&!($f<0||$f>$a||$k<0||$k>$a||!$i&&!
$j)}}$*=$e[$r][$_]=$h==3?0:$b[$r][$_]ne$"
&&$h==2?0:$";$d++if$*ne$b[$r][$_]}}@b=@e;
$d}{print"\ec",++$g,$\,map{@{$b[$_]},$\}
@a;select$&,$&,$&,.1;redo if&g}
[download]

Final update - by eliminating a few niceties (printing the generation number, allowing the program to terminate by itself), and accidentally creating a fractal, I chopped it down to 282 characters (not counting new lines).

@a=0..40;for$r(@a){$b[$r][$_]=!int rand
9?0:$"for@a}{print"\ec",map{@{$b[$_]},
$/}@a;select$&,$&,$&,.1;my@e;for$r(@a){
for(@a){$h=0;for$i($r-1..$r+1){for$j($_
-1..$_+1){$h++if$b[$i][$j]ne$"&!($i<0|$i
>40|$j<0|$j>40)&($i^$r||$j^$_)}}$e[$r][
$_]=$h==3|$h==2&$b[$r][$_]ne$"?0:$"}}@b=
@e;redo}
[download]

Final, final update Fine, fine, since this node is still getting some play and I have continued to tinker with it, here's a 270 character version. How low can I go, indeed.

@a=0..40;$b[$_]=[map{rand 9<1?0:$"}@a]
for@a;{print"\ec",map{@{$b[$_]},$/}@a;
select$&,$&,$&,.1;@e=@b;for$r(@a){for(@a
){$h=0;for$i($r-1..$r+1){for$j($_-1..$_+1)
{$h++if$e[$i][$j]ne$"&!($i<0|$i>40|$j<0|
$j>40)&($i^$r||$j^$_)}}$b[$r][$_]=$h==3|
$h==2&$e[$r][$_]ne$"?0:$"}}redo}
[download]

Now on to other things.