7" are not just singles necessarily... especially when you are talking punk there can be several songs on them. On the opposite side, I do have some 12" singles as well... which I do find to be much more pointless. I even had one once that had the same song on both sides, not even different version or anything.
I bet that Foo Fighters is what is more commonly known as a flexi. I have a few of those, including one from an old band I was in where I had to hunt a LOT to find a factory that still made them. They used to be found given away in magazines and things like that quite a bit. Sadly they usually don't sound very good and they wear out fairly rapidly if you play them more than occasionally.