Quite possibly
the single greatest invention in the history of mankind. I've never seen these back in
North America, only here in
South Korea. I don't know if they exist in other countries, but if they exist in yours, /msg me and I'll mention it here.
These are a brilliant form of advertising that someone (who I hope is now rich from the idea) came up with, and that many Korean businesses now employ. It's a round, plastic fridge magnet. On the front is the business' name, slogan, logo, phone number, etc. Here comes the brilliant part. On the back is a rectangular hole with a metal lip that works as a bottle opener!
The convenience is unbelievable. You open your fridge, grab a bottle of Hite, Cass or some other kind of Korean beer, close the door and there, right in front of you, is the tool you need to open it.
The method of getting them to the recipient is equally convenient. Apartment doors in Korea are made of metal. So someone just comes by with a bag of these things, and slaps one on every door in the building. I've have found six of them thus placed so far, and am taking five of them back to Canada to give as cheap-ass Christmas presents.
This method of advertising is especially popular among the fried chicken restaurants, since fried chicken is what most Koreans consider to be the best possible accompaniment to beer. So you're drinking your beer, you're feeling a bit hungry, you glance down at the bottle opener in your hand, and there's the number you need to order your chicken.
Sheer brilliance.
Note: I've been informed that they do indeed exist in North America, although obviously not in such proliferation as here, or else I would have seen them before.