Popup Windows

[jazzman170]

I was just wondering, how do we get popup windows to come up when you walk onto a certain tile? I was in a person's game called KirbyWorld, and they had a room with different sprites all along the walls. When you walked to the very end of the map behind the sprites, a popup window came up and it said in text at the bottom "would you like to buy this sprite for 10000 gold?" and along with a popup window of "yes/No" If this was hard coded then i hope to have it scripted soon, as this would be VERY usefull. I would love to have something like "Would you like to throw 10 gold into the pong?" "POPUP- Yes/No" then if yes, it calls a part of a script that makes you have a chance of getting double back your money, or a special item. like a 1 in 30 chance of getting a special item, and 1 in 15 of getting double your money. Not only that, but their would be SO many different types of things like that you could do. Quests and such too.