The Best one has to be the Rail Gun, and then he's making an upgraded one at that. OMFG! Looking at the power it requires one wonders if a laser would be better, but I think there is just something about projectile weapons we seem to really like.
The link for the Faceman(#19) internet remote has a typo in it. I would like something like that to control electrical use in my place. Use the web to turn the water heater on or off. I do think something like this would be best using the electrical wiring throughout the home as the network. For something like this, it does not have to be very fast.
I'm tempted to try my hand at the whole Maker scene by making an AeroQuad-like system. I might start off with a cheap 3-axis accelerometer stabilization and remote flight. Then later I'll see about adding additional axis and GPS for flight automation, maybe solar cells for prolonged flights.
It would be pretty awesome to make it capable of navigating from one coast to the other, with a cellular GSM module for communication for status updates and recieving weather information.