If you live in Seminole County, Florida, you can beat a breathalizer-based DWI by asking for the software source code on which the breathalizer runs. It seems that the source code is a closely-guarded trade secret the manufacturers don't want to reveal. Since a defendent is entitled to know how the incriminating machine works, if the State can't provide the answer they have to throw out the case.
This argument has apparently been rejected in other Florida counties, but at least it's another angle to try. Busted for speeding? Ask for the source code for the radar detector!
Link (via BoingBoing)