You can make it "enjoyable" by tying it to something else that you actually find enjoyable, especially if you limit the times you do the actually-enjoyable thing to the times you exercise.

I started mall walking in the winter when taking the dog to the park just stopped being feasible. I took along my MP3 player, loaded with good songs I hadn't heard in a while, and it was actually kinda fun. Then I burned some CDs for the car that had a lot of those songs on it, and I walk a lot less. It's not that walking has become more boring (cuz let's face it, it was pretty boring to start with), it's that the one thing I looked forward to about walking is no longer special to walking.