Define: Fun

I had a conversation with my friend over dinner which sparked me to think about what fun really is. He says that fun is the thrill in doing something that involves a lot of risk, but I say that can't one have fun just hanging out? For me fun is doing something that I have never done before such as hiking a mountain, or playing a game, or just being with people that make me laugh doing somethig random like watching a movie or just hanging out chillaxin. If fun is associated with a high degree of risk then I dont think I have really had a lot of fun in my life if I do not count those times riding up Tantalus in the car of Jessica Chang or riding the roller coasters at six flags, or going down the turny windy slide with my cousins at the water park. If fun is associated with a high degree of risk then the last time I had fun was last night as I rode in the car as my friend drifted turns and sped on the highway. It was exhilerating, but is this the same thing as fun?