XP Math is a good place to find math games, math videos, math worksheets, and math e-books. The games section of XP Math offers games for basic arithmetic, algebra, geometry, and probability. Create an account on XP Math and you can keep track of your scores.
Free worksheets on a variety of topic for language arts (reading and writing, grammar, spelling phonics, handwriting) as well as math, science and social studies. There are also brain teasers and teacher helper tools such as award certificates, teaching tips, etc. In addition, there are holiday worksheets. This site would be great for differentiated activities. In a quick preview I saw they had worksheets that were of the same topic areas but they has easy and harder options available. This would be another good site to share with parents.
There is a free trial version of the materials in the National Library of virtual manipulatives. Math topics Numbers and Operations, Algebra, Geometry, Measurement and Data Analysis & Probablity are covered. I did not come across anything asking for money so I a not certain there is a cost. There are tons of manipulatives to access from each of the above categories. This site is associated with the Uta State University.
Looks like an interesting site. Please share with anyone you feel may be interested. This is also another site to share with parents via your teacher web page.