Illustrative Mathematics Project has a module with a series of units that includes videos and links to illustrative tasks. Fractions Progression

Fractions predict future success in mathematics
This article from Mind/Shift looks at how to leverage what researchers know about brain science to ensure students learn. The focus is on learning fractions but would aply to any topic. A game, Frog Stone Island is linked, as a way to help students make connections with fractions.
Why think of fractions as a place on number line rather than pieces of whole.
Use a number line to convince students that fractions are numbers. Marilyn Burns blog
Marilyn Burns Blog about activity to order fractions

Web Sites and Applets

Fractions Apps: