This is probably one of the more unusual hands-on learning games that you'll find, but I guarantee you it works.
My husband and I are fostering two little girls, ages 5 and 3 1/2. They have been with us for nearly nine months. When they came to us, they suffered from some serious delays, so we went to work pronto on using every minute of our time to teach them, particularly the older one.
I find that the best way to teach kids with disabilities is to think of every minute as a learning opportunity. Initially it seems hard, but once you get into the habit of it, it will get easier and you will definitely get unbelievable results.
I used the vast amounts of street litter and daily walks- to the store, to visit a friend, etc.in order to learn colors. How? First I chose a color to focus on. We started with her favorite color, purple. I knew it was her favorite color because she always pointed to and requested items that were that color. Also, when I would ask her what color something was, she would always say,"purple," whether or not it actually was.
Each time I saw a purple ice-pop wrapper, potato chip bag, or any other purple object, I would point it out to her. She then ran to it and stomped on the item. If it wasn't stompable, we just touched it. When I saw that she mastered that color, we went on to a new color.
For this to work well you need to stay with one color until your child knows it absolutely cold. Then, when you go onto a new color, add on the new color as well. However, don't focus on more than two colors (one old and one new) at a time, because it takes away your focus.
Not only did she learn primary and secondary colors, she also learned "light" and "dark" as well as a few names such as turquoise and silver- all within about six weeks. I think that's pretty good for a 15 minute activity that requires no advance preparation!
A side benefit: her younger sister and brother (age 2 1/2) got so used to this game, that even after she no longer needed it, they insisted on carrying on the game! They were so determined to play, that I had to carry on the game with them as well.