Finger Physics [App Store] is a fully OpenFeint enabled physics game with multiple game modes, and with this recent update, a load of new content.
Gameplay is similar to ngmoco's Topple series with game modes that include building towers with different types of blocks (and even blocks that have special properties such as exploding blocks and magnetic blocks) as well as tapping blocks on an existing tower to guide an egg safely to the ground. There's also a lunar mode and an underwater mode that change how the blocks behave, requiring slightly different strategies to complete each level.
If you've enjoyed the array of physics games on the App Store, Finger Physics will likely be right up your alley. If you haven't yet experienced any of these games, Finger Physics is a great place to start especially during the current promotion allowing you to download the full game for free.
Finger Physics is currently appearing as free in the US App Store, since this change just went in to effect it may take a bit to update across all regions. If it is still 99ยขย in your store, check back later.
App Store Link: Finger Physics, Free (Until 9:00 AM PST 1/7/10)