<THIS DOES NOT WORK ON RETAIL>
Messing around on some private servers latley, I have found a nice warlock bug. This bug allows you to cast INSTANT shadowbolts for a certain amount of time.
What you need to do:
-Get a character that is at least level 25. (26 for higher proc)
-Spec into the affliction tree and spec into the talent "Nightfall".
No here is how this talent is bugged. On retail, when the talent procs you are awarded ONE shadowbolt free of any casting time, but on most private servers, the Nightfall buff will remain on your character for a little, while you spam SBs.
Enjoy!
P.S. To get the most out of this bug, it is reccomened you spend the rest of your points into the Destruction tree, not only to increase your damage/crit chance, but the talent Backlash also has a chance to award a free shadowbolt (this one will only last for one shadowbolt) and the Talent "Soul Leech" will heal you close to every time you spam a shadowbolt.