Well, even though you're on a bike, it's still a commute, so I don't expect it to be too exciting. For a while, I played games with my cycle computer -- highest speed, highest average, shortest time, etc. -- but that got tiring after a while, and my current computer doesn't have as many nice features. Sometimes I spend the time thinking about issues or problems, in my job, life, or from BikeForums! Lately I've been singing somewhat out loud, both because I feel like it and also to see how good my breath control is and maybe improve it. But I also really want to get a radio to listen to (I'll probably try to moderate the risk by having a plug in only one ear using a stereo to mono converter, or maybe a handlebar speaker), because that's the one thing I really miss from my car commuting days!