Back rev 1.3 out per Raymond's request.

Lib/this.py

@@ -20,4 +20,9 @@ Vs gur vzcyrzragngvba vf uneq gb rkcynva, vg'f n onq vqrn.
 Vs gur vzcyrzragngvba vf rnfl gb rkcynva, vg znl or n tbbq vqrn.
 Anzrfcnprf ner bar ubaxvat terng vqrn -- yrg'f qb zber bs gubfr!"""
 
-print s.decode('rot_13')
+d = {}
+for c in (65, 97):
+    for i in range(26):
+        d[chr(i+c)] = chr((i+13) % 26 + c)
+
+print "".join([d.get(c, c) for c in s])