What strange, old or interesting objects have you found?

I was watching Time Team on the television, plus the other day some people were walking along a beach in Tasmania (I think) and found the jaw and tooth of a prehistoric animal.

So what amazing things have you found? It could be a first edition in a book store or an 18th century bottle in your garden. Did you have it valued or do you just like to look at it? Or did you give it to a museum?