Tutorials in this topic are focused on special effects, such as strange phenomenons that aren't usually witnessed are are visually interesting.
Here's on I would like to share.
1. The split
I first saw it on 725dan-jail. Here's how to create it. Make a regionA with activation on Player/Character, activate a trigger that 'Harm the stability of players in regionA with power -50 ( enter any value that's negative, but keep it small, otherwise when you enter the region you get thrown into nowhere )
2. The static bullet
Ok if you've been playing superhero maps where you fly with defib, you've probably seen these things appearing. Somehow when a flying defib is used, static bullets appear in random places. Unfortunately they disappear after a few seconds and are uncontrollable in terms of positions. They don't cause damage or anything.
A flying defib is created by changing the projectile power and number of projectiles to a negative value.
3. Flamethrower
Ok this one is fairly complex, nvove-test that has it so go check it out. The problem with this is that the user receives damage from the 'flame' if he aims up. Still it's pretty cool.