The audience, as they were arriving...
Today I did a Science Club talk about exploding programs. The crux of the talk is that programmers (at least the better ones) should spend a lot of time worrying about what can go wrong with their programs, rather than just making them work. We took a simple application (pay the money out from a cash dispenser) and then had some fun finding out how it can go wrong, and what the programmer must do if it breaks. If you are a programming sort you can find the code here. I particularly like the sound that you get with a warning.
The sound it made when things went wrong was considerably enlivened by a fault in the playback method. It was supposed to just play an explosion sound effect, but for some reason it went a bit beyond that, making some amazing buzzing and crackling sounds. Fortunately the program kept going (it would have been rather embarrasing if the thing had crashed during a talk on software errors) and a good time was had by all.
If you give a talk at the Science Club the organisers give you a free box of Maltesers. Thanks folks, like getting sweets for having fun.