I've heard of this, but one thing I never got was wouldn't the detector thing that shows the interference patterns technically count as observing it?
No, the detector provides a method of interacting with the electrons, therefore upsetting the potential superpositions. I presume they used some sort of physical counter that relied on the electrons interacting with some part of the detector.
Electrons are a classic quantum particle, being both waves and particles at the same time, or somewhere in between. It's theorised that they travel every possible route at the same time, I'm not terribly educated in how exactly they choose which route but hey, you've got a near-infinite number of possibilities there, all calculated at once. For every electron.
If you can think of a way to measure something without observing its physical properties and behavior I'm sure every scientist in the world would like to hear.
FIRE NEUTRALINOS OR GRAVITONS AT THEM.