Intensionality is the key notion underlying the GLU system for coarse-grain parallel processing that has been developed at SRI CSL.
The language Lucid is a well-known example of an intensional programming language.
ISLIP is the name of an annual symposium series dedicated to languages for intensional programming. ISLIP 96 was held in May 96 at Arizona State University (Tempe, Arizona). ISLIP 95, was held at MacQuarie University (Sydney, Australia). ISLIP 95 proceedings are available as a book from World Scientific Press titled Intensional Programming I
ISLIP 97 will be held in Victoria, B.C., Canada.