All About Decimals
Naming, adding, subtracting, multiplying, dividing, rounding, place values, comparing, finding percents, equivalent fractions, and converting.

http://www.aaamath.com/dec.html

Decimal Concentration Game
Play a game of concentration matching decimals.
The pop-up box that tells you if you have made a mistake needs to be moved to allow you to see the playing board.

http://www.24hours7days.com/Javascript/Concentration/

FunBrain Decimal Football
How to Play: Enter your answer to the math problem and hit "Go".
If you are correct, the ball will move towards to goalpost.
If you are incorrect, you lose a down (a turn).
If the ball goes through the goalpost, you score.

http://www4.funbrain.com/cgi-bin/fb.cgi?A1=start1&A2=Easy&ALG=No&INSTRUCTS=1

Discovery School's Decimal Converter
Use this solver to convert decimals into fractions. 
Enter the decimal number you want to convert below. Then, click "Solve!"

Simulating Probability Situations Using Box Models
The interactive tool in this i-Math investigation is a "box model" that allows students to explore the relationship between theoretical and experimental probabilities. A "box model" is a statistical device that can be used to simulate standard probability experiments such as flipping a coin or rolling a die.

Combinations
This lesson focuses on combinations, a subject related to the probability-and-statistics strand of mathematics.  Students will be encouraged to discover all the combinations for the given problem-solving skills (including elimination and collection of organized data) and drawing conclusions.  The use of higher-level thinking skills (synthesis analysis, and evaluations) is the overall goal.   This lesson is taken from "Ideas:  Combinations" by  Marcy Cook that appeared in The Arithmetic Teacher Vol.36, No.1 (September, 1988) pp. 31 - 36.