(warning all code untested)

If you aren't worried about space, then that approach is fine enough, but perhaps:

@a = split /\s+/, join " ",
  ("1 " x 8, "2 " x 1, "3 " x 1);
print $a[int(rand 10)];
[download]

Is more(?) clear?

However, I would not approach it this way. Instead, I would do something like:

my %wheel = {"One" => 8, "Two" => 1, "Three" => 1};
my $sum;
my $item;
foreach $item (keys %wheel) {
  $sum+=$wheel{$item};
}
my $spin = int(rand($sum));
foreach $item (keys %wheel) {
  last if $sum < $wheel{$item};
  $sum-=$wheel{$item};
}
print "$item was picked\n";
[download]

I think that will work, if not, you should at least get the general idea.

G'Luck!
Gryn