Dirty, dirty little inkjet printer Answered
This one isn't really an instructable, because (duh) it doesn't actually describe how to make something, however, I think it might be of interest to some people of the same sort of mindset - it's about inkjet printers, and what you might find if you dismantle one.
I've taken quite a few apart (I work in IT and I have to dispose of them when they die) - they have something called a 'waste ink reservoir' - and it's quite surprising how much ink they actually 'waste' into it.
The Dirty Little Secret of Inkjet Printers
The 'waste' is ostensibly to clean the print heads - and yes, some of that is inevitable by nature of the technology, however, I'm pretty sure there are other motives behind it too - that ink ain't cheap...