How-To: DIY Tilt Switches Using Craft Beads
There are many different ways to build tilt switches, both in the factory and in the garage, but I like this idea from Instructables user fjordcarver to use unpainted metal craft beads (like those leftmost, above) like liquid mercury in a traditional mercury switch. His tutorial shows how to assemble two such vials to give an SPDT changeover tilt-switch.