Here are the most useful resources I've found and used in my years teaching middle school math.
PhET Simulations - Tons of simulations with lessons to go with them (a bit hit and miss but the simulations are solid)
Gizmos - Like PhET simulations but not free.
LabCamera - Chromebook app with a lot of science related features. Free for teachers but not students.
NGSS Standards from NGSS - Better view of the NGSS standards with lessons and labs for each one.
CK-12 - Free curriculum you can use and customize.