Turtlediary.com is a fun website for pre-K-2nd grade. They offer a wide range of activities including math, esl (which is basically Language Arts), and science games, experiments, videos, stories, worksheets, and more. You can play a a guest, create and account or purchase the upgrade. I just played with the basic account.
Here's the breakdown of what you get with each level. Under the Basic section (Free) you get access to the games, can create a favorites list and participate in the contests. They do limit how many games you can play.
If you join the membership you can have that and unlimited games, detailed reports, unlimited stories, unlimited worksheets, and NO ADS. This is $79 a year or $9.95 a month.
Pre-K (3-5 yrs)
Sight Words is a simple vocabulary and memory exercise for preschoolers. It is designed to introduce kids to some common dolch sight words. Early readers recognize sight words from having memorized them. In this exercise, kids will learn to recognize and recall dolch sight words by flipping the cards and making a pair of the matching words. Kids will enjoy as they sharpen their memory skills and build their vocabulary. This will help kids in improving their reading skills also.
It's a fun site and my kids really enjoy it. As for the ad's they didn't bother me at all. The videos are short but very educational and everything is on their level. Oh, and you can turn off the music and sounds, but that also means that there isn't anyone to read them the directions in the games. I didn't get to see the assessments because I only tried the free basic portion and it doesn't move your child along as they learn the skills so you have to be around to make sure they aren't playing a game that is to easy or to hard. Other than that it's a great site and one I would encourage my kids to play on regularly.