Jumping at a certain angle on a cylinder block to get a boost
This is not actually the correct explanation of the glitch. The glitch (as coined by Gamefandan) is called the "Super Jump" glitch. It occurs when your jump trajectory takes you right up against another object you can jump against, and even though you're not quite touching it it still registers you as having jumped again, so it adds to your vertical velocity, causing you to go further. The glitch can be done on regular blocks, players, and even map geometry (though those are gone now.)
Another glitch is that if you jump, crouch and uncrouch with the right timing underneath a flat plate with raycasting off, you can clip up through it and land on top.
