So back when SL was pretty glitchy I managed to break it during 2008. I was actually able to get underneath the solid ground that objects otherwise couldn't pass through and I saw SL's version of 'Blue Hell'.
In most cases objects would fly back up like a rubber-band and you couldn't get through (if you tried to move them under the ground). I couldn't tell if it was the scripting of the vehicle or it's general shape that caused the glitch but for awhile I was flying underneath and it was an experience.
Then there was another glitch where if you tried to crouch and held the key down as you ran your avatar would 'zoom' across the map like it was shot from a cannon then return back to it's original spot when you let go of the key.
There is so much I can say on this, SL itself is a engineering marvel. It uses a modified version of the Havok engine which is ancient by today's standards. There's elements of platforming and momentum your av gets. Granted it's very little.
Amazing how it can run all of this knowing how much of a ambitious project SL is. I'm not sure most people realize what goes into SL's technical side of things to get it working.