tinyTesla Musical Tesla Coil Kit. tinyTesla is a DIY mini musical Tesla coil kit that anyone can build. Once complete, tiny Tesla shoots 4 inch sparks (tiny lightning), plays music and wirelessly excites fluorescent tubes.
Algae Lamp Absorbs 200-Times More Carbon Dioxide Than Trees, Doesn't Require Electricity - TechEBlog
Bike light. Creates a laser bike lane so cars leave you enough space.