Padlock Shims
It is possible to open a padlock by simply slipping padlock shims in between the shackle and the lock's casing. Wiggle the shim gently until the shackle pops up, the picture below clearly illustrates how this works. This technique is nice because you get to ignore trying to defeat the actual locking cylinder where the key is placed.
Padlock shimms are very easy to make, here is a quick example:
Added By JoshuaCodyWilson
in some cases, cases in which the shackle has 2 locking mechs, you would need to use two shims. one on each side...
Added By Atomicmuffin
and of course, ball bearing locks cant be shimmed...