> All that said, I can always be annoying if I wish - watch your machines
> memory and cpu when fed this:
> 
> str = "x = []; 0.upto(1.0/0) { x << Class.new }"
> 
> Hope this thread managed to convince you that running code received from
> users (or otherwise untrusted) is always a Bad Thing(tm).

You get five seconds. Then we kill your thread.

symbol memory exhaustion is one unsolved issue, though.