If your Windows Phone 8 device has NFC (Near Field Communication) support, you may want to take a look at the Windows Phone game Grow.
Grow is a simple game where your success is dependent on how much you use NFC. You have a potted plant that grows the more you use your NFC and as a bonus, you can view the map (little icon in the upper right corner) to find additional Grows for bonus plant food. Grow comes across as a game that is part virtual pet and part scavenger hunt.
Grow isn't an action packed game for your Windows Phone but if you've been looking for an excuse to use your NFC on your Nokia Lumia 920 or HTC 8X, Grow might fit the bill.