I like Serena
I've followed this one with interest since its introduction.You mean ones like http://en.wikipedia.org/wiki/BMW_C1 ?
My personal theory is that they designed that just to prove that Germans DO have a sense of humor. But they have at least one customer in the UK, because I once saw him riding it!
It's a car with the advantages of a motorbike!
It has seat belts.
You're allowed to drive it without a helmet, because this is the only motorbike that prevents your head from hitting anything.
You're dry in the rain.
But it's still narrow enough to drive through traffic jams and to park on the sidewalk.
I'm still wondering why it's not more popular!?