piranha@gtv ~/test>cat fac.rb
def fac i
    if i == 1
        i
    else
        i * fac(i-1)
    end
end

1000.times { fac 200 }
piranha@gtv ~/test>cat fac.py
def fac(i):
    if i == 1:
        return i
    return i * fac(i-1)

for i in xrange(1000):
    fac(200)
piranha@gtv ~/test>time ruby fac.rb
ruby fac.rb  0.42s user 0.03s system 99% cpu 0.452 total
piranha@gtv ~/test>time ruby1.9 fac.rb
ruby1.9 fac.rb  0.29s user 0.00s system 96% cpu 0.302 total
piranha@gtv ~/test>time python fac.py 
python fac.py  0.10s user 0.01s system 100% cpu 0.111 total