that is, a sale that forces people to buy a game for higher than its base price?
you know how in a sale you'll see the normal price with a slash through it and then what the sale price is and how much % off the norm that is? i want that except that it shows you're paying 80% more than the normal price. also it would be cool if people could see how long until the anti-sale is over. just like with sales.
I just had a look and tried everything I could. I'm assuming that if you were to put on an anti-sale you'd have to set the discount figure to a minus number (so if you wanted to double the price, set the discount to -100%) however because this works on a slider system which starts at zero and not a type in system, such a "discount" isn't possible and even if it was it'd likely be coded so that you couldn't input a negative value. (An anti-sale is something I've never encountered and is completely new to me.)
I'd say the best way to achieve this would be to do what SolarLune suggested and raise the minimum price temporarily then lower it again when the anti-sale is over.
I have to ask though just out of curiosity, why would you want to do this?
I could think of a few reasons, a unique marketting angle being one. It might have some interesting effects on consumer behavior, most people wait for a sale to go on to get a game cheap, this would basically be the same in reverse so consumers would wait for the game to go back to "normal" presumably. If nothing else its seems like an interesting little experiment.