I read about this somewhere years ago and it has worked like a charm every time.
Either using your old beer or buying a cheap can of it, pour some into a shallow dish, cover with saran wrap and then using a fork poke one set of holes in it. The fruit flies love beer. I don't know why, probably because they're Canadian (ours are anyway). They go in the tiny holes by the scent and can't get out. Mu-ah-ah-ah. I put two out in the kitchen and one in the bathroom. For some strange reason they always find their way there and this week, in masses! Its terrible. So here's a snap shot of the ramican in my bathroom... and by complete coincidence, the bar of soap I have out right now. I have NO idea why my toddler is too wigged out to use the soap right now.
