Well I was doing my daily browsing of the interwebs when I came across this video that might come in handy if you're ever stranded in an icy wilderness, or you just want to burn some ants and you don't have a magnifying glass.

Not that we really get much ice here in Texas and we certainly don't need to be starting any fires with all the drought conditions, but when I saw this video, I thought it was pretty cool.  Never thought about the idea myself, but it makes sense.  Check it out.