If you dont know, garry's mod is a mod for HL2 which allows you to basicly spawn, and mess around with all of the objects in HL2 and play with physics and a little GUI enabled scripting etc...
Ive seen some amazing stuff, really, player created vehicles made out of cargo crates, fully functional aircraft, breakdancing mechanoids, paintcan launchers etc etc etc...
http://video.google.com/videoplay?docid=8926325136071596338&q=
If you've ever used garry's mod then you will know how difficult and time consuming this would have been to make.
Ive seen some amazing stuff, really, player created vehicles made out of cargo crates, fully functional aircraft, breakdancing mechanoids, paintcan launchers etc etc etc...
http://video.google.com/videoplay?docid=8926325136071596338&q=
If you've ever used garry's mod then you will know how difficult and time consuming this would have been to make.