"to school" versus "to garage" [duplicate]

Possible Duplicate:
Is there a reason the British omit the article when they “go to hospital”?

Why is "I am going to town" or "I am going to school" acceptable but "I am going to garage" not acceptable? Is there a term for this kind of exception on the use of definite/indefinite articles?

The zero article is used when places are regarded as institutions, so we talk about going to church, going to jail, going to university and going to school. It might just about be possible to argue that going to town fits the same pattern, but it must otherwise be regarded as anomalous. A garage clearly cannot be seen as an institution and so requires the definite or indefinite article, depending on context.