There are a lot of ways to avoid tedium in your workouts and keep you motivated but the top approach is to schedule workouts with your friend for consistent days and usual times. To successfully do this, find a friend whom you believed that there will never be dull moments spending time with him and who is also physically enthusiast.
Moreover, having an exercise buddy is a good source of physical motivation for he can encourage you to try different kinds of workouts while also enjoying different types of music and smart conversations.