Check out this strategy puzzle game for the iPhone.
There are some promo codes available to download it for free:
7HFERFYFP9KA
FFHY6JLW3Y46
NAANKHRHYWTK
MEN33KRLLHF3
JAHHT3XLYHRA
AJNN477EHNW6
AKL4X6AMT7NJ
HFP94PJYEXHP
These will only work once each, so when they’re gone that’s it. 🙂