From an English perspective, I would recommend you have your students read a magazine like Make (http://makezine.com/) or a website like Instructables (http://www.instructables.com/home) with a two-fold goal. First, either individually or preferably in groups, the students should create one of the projects they find (with instructor and parent approval). Second, again individually or in groups, they should create something new and post the what they did and the results. Both of these could easily be joint projects between science and English instructors. Personally speaking, I'd be really interested in what 8th graders would choose to make, and would therefore really would like to see what they publish. You might even be able to strike up a deal with the folks over at Make to have a special 'middle school' edition with projects from students around the world. One of the popular concepts in instructional technology right now is 'authentic' learning/problems/assessments, and between the creation of something new and writing it up for publication, I can't think of anything more authentic to encapsulate both science and English at the middle school level.
I'd also strongly suggest having them read a classic scifi book (http://home.austarnet.com.au/petersykes/topscifi/ lists_books_rank1.html; and I'd highly recommend the Red, Green, Blue Mars trilogy by Kim Stanley Robinson) then do a report or class presentation including (a) what science was fiction when the book was written, but is now real (think tricorder), (b) what science was fiction when the book was written, but is based on real science (think anti-matter in Star Trek), and (c) what science was and appears to be fiction (think faster than light travel).