Speaking of ninja tricks...
There has been some talking about ninja tricks, and I thought: could you name me all the ninja tricks you know?
Right now I know:
Cube throw: (throwing a cube to hit a button)
Cube jump: (cube flying through 2 vertical portals and then jump onto the cube to reach platform)
Vertical portal jump:
Turret climbing:
Portal bumping:
Pictures are welcome 
no climbing on them, as i showed in this video: wLlvBAi10m0
When walking on catwalks, go to the press A and W at the same time to move faster.
Portal Bumping.
Portal Bumping.
I can't seem to get that working
Many people get that working in the catwalk stairs in the elevator, they call it wall strafing, works with some surfaces too.
Also portal bumping works with glass frame props, so look for a map with a frame for glass, and it's in between portable surfaces. I found one in the collaboration course.
I think Valve got lazy after mapping for the SP campaign.
I found misaligned textures, they forgot to add portal bumpers, the outside of the walls have no nodraw textures, just bts textures (why it's laggy), and some of them are sloppily done.
Also portal bumping works with glass frame props, so look for a map with a frame for glass, and it's in between portable surfaces. I found one in the collaboration course.
I think Valve got lazy after mapping for the SP campaign.
I found misaligned textures, they forgot to add portal bumpers, the outside of the walls have no nodraw textures, just bts textures (why it's laggy), and some of them are sloppily done.
I noticed some of those things as well, however about the nodraw textures: I thought that textures that only touched the void didn't need to be nodraw?
Anyways about the portal bumping: here's a great vid (portal one, but still works in 2:)
kVDnuuqFfek
Oh yea portal bumping Gooood idea 
The wall strafing makes you go a little faster, but could be used as a map element?