I haven't done one of these for a bit and this one won't be too long. But here are some fun hacks.
Skulladay: puts up or creates a skull image every day.
Jointmaker: a new kind of hand saw.
Springfield Middle School Tilapia Project
Brass Rocking Horse
Famous Hacks from NASA
Growing Silver Crystals
Media stand furniture: looks a bit like some old Chinese furniture I saw in a museum once
1o1 Crafty Ideas
Blue Tooth Robot
DIY Fusion Reactor: I don't think he's kidding