sub timestamp
{
    my @st = localtime (shift);
    return sprintf "%04d-%02d-%02dT%02d:%02d:%02d.000-0700",
        $st[5] + 1900, ++$st[4], @st[3,2,1,0];
    }

sub starttimestamp  { return timestamp (time);             }
sub endtimestamp    { return timestamp (time + (15 * 60)); }
sub futuretimestamp { return timestamp (time + shift);     }

my $fts = futuretimestamp (162 * 60 * 60); # Stamp 162 hours ahead