If the cool breeze from your USB-powered fan necktie isn't doing enough to keep your sweating under control, pairing it with the USB Air Conditioned Shirt by Kuchofuku (of air conditioned bed fame) might do the trick.
The shirt, as its name suggests, contains USB-powered fans that blow fresh air inside your shirt when you plug the garment into a USB port. Which means you'd best remember you're plugged in when you stand up. And which also means that if it's really hot outside, you're going to have to drag your laptop with you if you want that portable refreshing breeze. In that latter scenario, the old-fashioned paper-folded-into-a-fan might be a better look.
The shirt sells online at the Japan Trend Shop for $169, and if the photos on CraziestGadgets.com are any indication, it will puff up to make you look like a skydiver, a comfortably cool skydiver.