I recently finished the first version of an android client to connect to the linux bitcoin client running in daemon mode and provide a UI. I was looking for an excuse to learn some android around the same time I became interested in bitcoin and this was the result.
* View server information (including balance, number of blocks, etc)
* Send bitcoins
* View recent transactions
* Manage accounts and addresses
Half way through working on it I found out that someone had made essentially the same thing (called bitcoiner) but I decided to complete mines anyway, for the sake of learning. Hopefully it'll offer something different, but unfortunately I've not been able to check as the market page says my phone can't run bitcoiner (for some reason). However, I believe the feature of managing addresses and accounts is different.
I enjoyed working on this and found out I love android - I've never seen anything that's better documented. I'd appreciate any feedback or suggestions!
Also, thanks to the guys in #bitcoin-dev who patiently helped me get to grips with some RPC issues.