Thought I'd share a few techniques that I find to be comedic in use. They do have some real competitive applications, but that doesn't make them any less silly.
Snake: Rocket sliding. This is more than simply canceling your dash into an up smash; the difference in sliding distance is quite noticeable. You will need default or similar control settings to pull this off. Begin a dash, then immediately c stick down to perform a dash attack, then immediately hit up and z (grab) to cancel the dash attack into a sliding up smash. You can cross about half of final destination with this. Squirtle can perform a similar technique, but it is much more difficult.
Lucas: Momentum changing. To do this you will need to set c stick to special (b button). Simply run and jump in the direction you want to go and then hit c stick in the opposite direction. This will perform Lucas's side special in the air, but force him backwards after it, drastically changing his momentum.