"your download has just finished" popping up in your iphone when you're on the go (or at the pool), or the latest tweets from friends (using Adium), or even get

"your download has just finished" popping up in your iphone when you're on the go (or at the pool), or the latest tweets from friends (using Adium), or even getting notified when your friends log on to Xbox live are examples of some quite interesting general public things that can be done...