If you walk towards a chest and jump just as you are about to hit it, there is a slight chance that you clip straight through the chest and find yourself inside it. You can then jump to enter nearby chests. The attached video describes the glitch better than I can, so I suggest watching it.
MC-7856
Chests - clipping
Resolved
Duplicate
0
Eric Ne
(Unassigned)
Unconfirmed
Minecraft 1.4.7
Retrieved
Duplicate of MC-1635 , please use the search function to see if your bug has already been submitted. Currently over 45% of tickets are being closed as duplicate.