my @arr = ('A'..'Z');
my $combo = join '', @arr[rand @arr, rand @arr];
print $combo . "\n";
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see Slices

Another way using the core module List::Util

use List::Util qw(shuffle);
my @arr     = ('A'..'Z');
my $combo   = join '', (shuffle(@arr))[0..1];
print "$combo\n";
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Your solution, toolic, is nice but not equivalent to the original script; the original could choose two elements that are equal; yours can't... ;-)
[]s, HTH, Massa (κς,πμ,πλ)

A little more generally you could:

  my @arr = ('A'..'Z');
  my $n = 2 ;
  my $combo = join '', map { $arr[rand @arr] } (1..$n) ;
  print $combo . "\n";
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which will give you any length string you like.

Whatever you do, don't do:

  my @arr = ('A'..'Z');
  my $n = 2 ;
  my $combo = $arr[rand @arr] x $n ;
  print $combo . "\n";
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however plausible it might appear :-(

Of course it doesn't work, you say, it's obvious... However, I have, ahem, a friend who once (once was enough):

  my @arr = ([]) x $count ;
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and had a lot of fun (tm) working out why their program behaved as oddly as it did !

many thanks!

Or even...

my @arr = ('A'..'Z');
my $n = 2;
my $combo;
$combo .= $arr[rand @arr] for (1..$n);
print "$combo\n";
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my @arr = ('A' .. 'Z');
my @combo;

my $n = 2;

# keep at it till we get $n random values in one pass
do {
    @combo = ();

    my $i = 0;
    rand(1) < $n / ++$i && splice(@combo, rand(@combo), $n <= @combo, 
+$_) for @arr;
} while @combo < $n;

print "@combo\n";
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