have you ever owned (or still do own) the game super Mario bros? know that ending in world 8-4? it may seem there is only 32 levels but as it turns out there is 33 (35 for the family computer thingy version) the 33rd (34th and 35th for another version) can be done doing a simple but tricky glitch:

1. go to world 1-2 and go to the end of the level as big Mario (or big luigi)

2. DO NOT go to the warp zone as that is the key part of this glitch not break the 3rd and 2nd blocks until the green pipe

3. crouch down and jump to the right  repeat this until Mario or luigi slips into the warp zone now that may look like your ordinary warp zone but here's the thing: the first pipe will take you to the minus world 2nd will take you to world 5 if you let the 3rd pipe apere  the glitch will break I will not spoil the result for you as you may be I tiny bit disipointed if you are playing with the NES version