Terrafirmacraft (http://www.terrafirmacraft.com) is a total conversion mod for the wildly popular game Minecraft (http://www.minecraft.net - although if you haven't heard of this, do you even play games, bro?)
One of the aspects of the game is mixing various ores to create stronger alloys. Later in the game, you get a crucible that allows you to see the percentages of ore/metal that you currently have so you can see if you need to add more of a specific metal to create what you're looking for.
Before you get to the crucible stage, however, you have to put ores blindly into a vessel and throw it in a pit kiln and hope your math is accurate. That's where my Terrafirmacraft Alloy Calculator comes in to save new players and those who are bad at math.
The interface is similar to the UI seen in game, so it's instantly familiar to players, and it allows you to mix and match ore in a vessel and see what their outcome will be.