Mosquito solutions

This summer hadn't been too bad in terms of mosquitoes around our house, but in the past couple of weeks, their population seems to have exploded! I can't even walk to the mailbox without getting bitten at least twice. On top of that, I seem to have some sort of reaction to the local breed - I get nickel-sized welts that will hurt like heck for a couple of hours, then disappear, only to reappear two days later in the middle of the night and have me in a scratching fit first class.

I try to avoid being outside after dark (that's when it's really bad), but I also have things to accomplish outside, and I flat out refuse to give those pesky bugs the satisfaction of beating me into retreat. So, unless it's really hot, I will wear sweats and a long-sleeved shirt - that way, I can apply the bug spray mostly on my clothes. I have noticed that my skin seems to get "warm" if I apply spray directly to it, so I try to avoid contact as much as possible. Don't get me wrong, I HATE having to apply bug spray, but, unfortunately, anything containing a generous amount of DEET seems to be the only remedy that actually works when it comes to our Minnesota mosquitoes. At least I haven't found anything less toxic that works as reliable - if you have any recommendations, I'd love to hear them. We will be going hiking at the North Shore in a few weeks, and if there's anything I can use instead of toxic chemicals, I'd be open to try it. Has anybody tried these new "personal shield" thingies that you clip onto your belt? How about ultrasonic devices? Any non-DEET-based sprays or lotions out there that work?