Here are some websites to check out... mostly beneficial for middle grades science curriculum.  Sorry, not all are interactive - some are in-class projects...

http://www.k12science.org/curriculum/drainproj/information.html

http://library.thinkquest.org/J002289/meta.html

http://pbskids.org/zoom/games/3puckchuck/

http://www.educationworld.com/a_curr/curr019.shtml