The rail cannon is back from THUG1. Just take the rail tool and create a tall M. Have the first rail you place at the top, second at the bottom in the middle, and third at the top. Now just grind the middle of it. Your skater will get stuck for a second and then fly up into the air. While in the air you can press the trick modifer buttons like o + o and it still thinks your grinding and a new trick name will come up.
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