The following code takes a positive integer command-line argument (<306) and tests to see if it is prime. In a very, very, silly way.
eval or exit print "$n is not prime.\n" for
<@{$"=',',[$n=pop]}-1/(1${\("/{@{[2..1+$n/2]}}"x2)})|0>,'
print "$n is prime.\n"'

[download]

Edit:Modified code with |0 to stop it claiming 98 was prime.

In reply to Testing for prime-ness, the silly way by Dedalus

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