I feel obliged to point out that C++ is C postincremented, that is to say it has the same value as C, but after you read it C gets incremented. The metaphor is flawless.
By the same token, the sharp sign in C♯ is two plusses put together, and represents going a (half) step above C. Also, a minor second is one of the most dissonant intervals in western music, which is also a brilliant metaphor for how well C♯ meshes with C.
