This is overwhelmingly a visual-spatial game; once you read the rules, the only other thing you need to read is the row of percentages on the back of each card. The front has abstract art in red, yellow, green, and blue. (Obviously, this is not a game for colorblind people. Those who can see color and shape but not read fine print might do fine. YMMV depending on how your eyes work.) First you draw an arrow card to indicate the color in play. Then you place cards with increasing amounts of that color in the direction of the arrow. So if the card is blue, you put down cards based on increasing blueness.
There are many different shapes in play -- squares, triangles, circles, question marks, flowers, letters. You have to look at the abstract art and try to figure out the proportions of the target color. This is a lot harder than it looks, because often the colors are only one or two percentage points apart. If you think the lineup is incorrect, you can challenge it. Flip over the cards and check the percentages. If you're right (and the line is wrong) you get the arrow card; if not, the previous player gets it. The first person to collect three arrows is the winner.
I'm only somewhat good at it, but I love just looking at the different shapes. Plus, once you know the concept, it's very portable -- you could play this with any set of images, or make your own. T-America probably has a jillion different decks of this, including ones for famous abstract artists. Hell, now I want a Frank Lloyd Wright deck. >_< The tricky part would be calculating the actual percentages to put on the back of each card. The original deck is huge, though; you won't run out of cards soon. As another variation, you could play solitaire just by seeing how far you can get before you make a mistake.
If you are looking for a game to enjoy with less verbally oriented people, Illusion is a great choice. It really stands out from the usual run of games based on words or dexterity. Artists and other visual thinkers will love the hell out of this. (Be prepared for distractions talking about the art itself. As an alternate activity, it's a terrific tool for discussing color and composition in art.) English language learners and small children can play as soon as they understand the basic concepts of "more color" and "going in this direction." We really had fun with it, and I think that other folks in our community will enjoy it too.