I bought some neomidium (sp) magnets a while back. They are about 1/2" in diameter, and 1/8" thick. They are awesome. I have been putting them to all kinds of uses.
I got out my Zircon stud finder to locate a stud today, and was confused as to just where the studs were. Sometimes, the beeps and lights are hard to read, and sometimes, really obvious. I went and got a stack of about 12 of the neomidium button magnets. I slid them along the wall, and when they would stick to the nail heads, I just left them there. In no time, I had a VERY accurate image of where the studs were by the buttons sticking to the drywall.
If you ever see these magnets, they have a million uses, and are remarkably strong. Not very expensive, either.
Steve