Today, a picture from the lab I work in. We were troubleshooting a piece of equipment, and decided that some pictures would be helpful...
This is the tip of a helium-3 cryostat. Without going into the nitty-gritty, it's a device that can cool things down to roughly 0.3 degrees above absolute zero.
We were trying to figure out why one of the coax cables, the one right next to the penny, was working fine when the system was on the bench, but died once we tried to cool the thing down. We finally managed to track the problem down to thermal contraction (as things cool, they tend to shrink) causing the wire to slightly pull away from its connector.
The penny, by the way, is there just to give scale to the photo. It's not actually used during operation...