Try this:

my @data = <FILE>
my @new_data;

chomp @data;

while(@data) {
  push @new_data, join(' ', shift(@data), shift(@data));
}
[download]

This is, of course, assuming that your text file contains 'paired lines'.

There might be a map trick you could use too, but I can't think of how you would do it in 3 minutes :)