
: I love the idea of an inflatable 1-mile long sign.... It will be a
: really neat thing to see it explode when a bolt  (or even better, a
: Westford Needle!) comes crashing into it at 10 clicks a sec.  

: <BOOM!>  Whooooooooshhhhhh......  <sputter, sputter>

: <okay, PRETEND it would make a sound!>
                 ^^^^^^^^^^^^^^^^^^^^^

Just a thought... (let's pretend it IS INFLATED and PRESSURIZED) wouldn't
there be a large static electricity build up around the puncture?
If the metalization is behind a clear sandwich (ie. insulated) then the 
deflating balloon would generate electrical interference - "noise"

By the way, any serious high velocity impact would simply cut a "Bugs
Bunny" hole through the wall, highly unlikely to "BOOM", and the fabric
would almost certainly be ripstop.
