My 10-year old son has been interested in biking for years; he has spent a lot of time on a bike ever since he was able to ride without training wheels at 5-years old. Last year, I bought him his first road bike, a Giant TCR, X-small. He loved it, but I quickly discovered that riding with him was a test of my patience. I was good to him; didn't blast up the hills or set a high pace, but the experience wasn't enjoyable as it could have been for either of us because of the disparities in strength and training. He still did well, completing several 50+ mile rides with monster hills... but I started thinking about getting a tandem after one of these long rides that took 4.5 hours.
We bought our tandem towards the end of the summer, and it was the answer to all our problems. I could ride to my potential, and he got to attain speed that he could never experience on his single bike. We logged lots of long rides on the tandem with several centuries and a couple of organized rides (one was the Hilly Hundred, near Bloomington, IN). Now that it is cold, we don't get out as much, on our single bikes or our tandem, but we're planning for the next season. My son is so excited about upcoming organized rides. When we get fliers in the mail, he avidly pours over them, begging to go. He's totally addicted... and I couldn't be happier. And I'm glad that I didn't have to do anything to fuel his addiction except provide him with good equipment, offer encouragement, let him have a say over what routes we take, and try to plan fun trips.