We've been working with the team at BBC Bitesize for a year or two now. Last year we worked on a suite of GCSE revision tools for conventional smart- and feature-phones, which took in a large amount of quiz-related content and churned out simple Java apps. They're quite straightforward: each app covers a single subject and contains a database of multiple choice questions organised by sub-topic.
We're quite comfortable with the technical and UI side of this sort of thing; the biggest problems were probably around the automation of builds (there are quite a few versions of the product for different subjects), and the inclusion of the quiz content: a quite large pool of questions, answers and imagery which needed to be folded, spindled and mutilated in various ways for different screen sizes.
Early this year, the BBC came back to us and asked about taking the product onto more modern smartphones. With a relatively simple product, a limited budget, and a brief to go as far as possible on modern touch devices, this seemed like a good opportunity to see what we could deliver with HTML5. The work itself was fairly straightforward, and much of the original user interface didn't need to change significantly as we moved from keypad-and-menu to touch-based devices. We were also pleasantly surprised to discover how remarkably consistent browsers were between iPhone and Android, but see for yourself - the quizzes are all available here.
I'm also pleased that we managed to tie this work into the W3C Mobile Web Application Best Practices effort which I've been extremely tangentially involved in, by submitting an implementation report based on the project. If you're working on mobile web applications, I'd encourage you to do the same.