I tend to record everywhere I go and have specialised on recording of sound for design and composition purposes as well as field and location recording. A few gems are shared on Freesound.org.
Among others, one of the more popular downloads I posted is a flyover of a landing aircraft recorded in London, near Heathrow airport. I was recording together with a friend of mine using a Tascam DR-60 and Zoom H2 together with a Sennheiser shotgun mic.
Two other heavily downloaded sounds are my light bulb recordings (or this one). Both were made when I was visiting my parents place, using my self-made piezo pickups together with a small, first-soldering-experience amp, bought at a local electonic shop.
The piezo pickups are an incredibly valuable addition to my ‘microphone’ collection as they can go into the smallest spaces, they can be used without any problems in water and using a strong preamp even seem to be able to pick up sounds from the air. Of course the tiny brass plates have their restrictions regarding frequency response, but as intimate close-ups I would not want to miss them.