To grab the BibTeX between the <bibtex> and </bibtex> tags in an article, simply visit Special:BibtexExport/Article_Name.

To narrow it down you can append a query to the URL. For example, if you wanted to get the bibtex for all the Haystack publications by David Huynh in the year 2005, simply visit:

http://simile.mit.edu/exhibited-wiki/Special:BibtexExport/Haystack?field:author=David%20Huynh&field:year=2005