fib.py

def fib(n):
   if n == 0 or n == 1:
      return n
   else:
      return fib(n-1) + fib(n-2)

for i in range(36):
    print "n=%d => %d" % (i, fib(i))

# Python 2.5.4
# $ time python fib.py
# real  0m25.760s
# user  0m25.103s
# sys   0m0.178

fib.rb

def fib(n)
  if n == 0 || n == 1
    n
  else
    fib(n-1) + fib(n-2)
  end
end

36.times do |i|
  puts "n=#{i} => #{fib(i)}"
end

# ruby 1.9.1
# $ time ruby fib.rb
# real  0m10.230s
# user  0m9.953s
# sys   0m0.080s

fib2.py

def fib(n):
    a, b = 0, 1
    i = 0
    while i < n:
        yield (i, a)
        a, b = b, a + b
        i += 1

for i, f in fib(36):
    print "n=%d => %d" % (i, f)
    
# Python 2.5.4
# $ time python fib2.py
# real  0m0.029s
# user  0m0.012s
# sys   0m0.013s

fib2.rb

fib = lambda do |n,b|
  i,k=0,1
  n.times do |p|
    b[p, i]
    i,k=k,i+k
  end
end 
fib[36, proc {|i, f| puts "n=%d => %d" % [i, f] }]


# ruby 1.9.1
# $ time ruby fib2.rb
# real  0m0.019s
# user  0m0.011s
# sys   0m0.008s