Not a code to deploy but on the address bar of an old kiosk browser. An ugly JavaScript script to escape the computer lockdown and access the filesystem. Always nice to debug a one huge line of JavaScript that outputs HTML/ActiveX.
I also vaguely remember escaping some "internet cafe" kiosk at some hotel during one of the abroad school trips. The kiosk had "broken" sticker on it and seemed actually broken, but some functionality still worked and after escaping the kiosk UI I was able to actually fix it (as we actually wanted to use it) - don't remember what was it though :( Some technician was probably either grateful for a null job afterwards, or lost an order due to me ;)