Cool one liners for the Fibonacci series? Sure, there are bunches of them. Here's one that I wrote during an email exchange on the subject in which I was dared to "do something with bitwise ops":

perl -le'map{$_=$b.$a|"~",$b=$a,$a=$_,print}1..pop' 10
[download]

It doesn't just compute the series but also graphs it.

In the same exchange, the author of the dare (who shall remain nameless) also made the wisecrack that "recursion is for wimps." That compelled me to trot out the old Haskell classic:

fibs@(_:x) = 1 : 1 : zipWith (+) fibs x
[download]

That's it. The whole infinite series. Want the first 50 elements?

Fib> take 50 fibs
[1,1,2,3,5,8,13,21,34,55,89,144,233,377,610,987,1597,2584,4181,6765,10
+946,17711,28657,46368,75025,121393,196418,317811,514229,832040,134626
+9,2178309,3524578,5702887,9227465,14930352,24157817,39088169,63245986
+,102334155,165580141,267914296,433494437,701408733,1134903170,1836311
+903,2971215073,4807526976,7778742049,12586269025]
[download]

Fun stuff.

Cheers,
Tom