Some of the craziest, most useful glitches in Minecraft Xbox 360 edition?

Does anybody know some of the craziest, most useful glitches in Minecraft Xbox 360 edition?

Added (1). I have been searching and searching on YouTube and the web, but just can't find any glitches that I can use without downloading a MOD.
(P.S. I'm 12 years old)

I do not have monster spawners unless I find one. Can I break one with a piston, like an ender dragon egg?

Please notice: I do not get to play games too often, so I might not get to try all of your answers.