I (Mr. Fozzie) am American by birth and I can pretty much assure you that Americans don't really know what crackers are (apart from Saltine crackers which are a type of biscuit similar to Carrs water biscuits but FAR superior).
If you are able to find them anywhere in the states you'll find them in a shop that has a "foreign foods" type section. Apart from the lack of availablitly, Americans think the idea of sitting around a table wearing paper crowns rather silly. I've been here for 17 years now and I still can barely suppress a snicker!
(This reply has been sent without Mrs Fozzie's approval who is British and LOVES Christmas crackers. In fact, she has now sworn to make me wear a paper crown this Christmas whether I like it or not!)
The Fozzies