I am resurrecting Countdown Timer from, oh, about, 4 years ago! I have yet to find a simple timer app for iPhone that I like; so why not make one myself?
So, it’s not an iOS app (yet…), but to get it running on the mobile, quick-and-dirty-like, I used processing.js to throw it into and HTML5 <canvas>. I have also begun re-working the controls to be more touch-appropriate. For example, it no longer relies on keyboard input to adjust the time; now you increase and decrease the time in 5-minute increments by simply tapping (or clicking) in the top or bottom half of the page.
There are still a few kinks to work out and some maths to tweak, but I think its a pretty good proof-of-concept for ~20 minutes of work.