Nothing motivates me better than a song I can rock out to. Find a genre that gets you going and build a workout list to pump you up! Before you know it you are going an extra ten minutes to hear your favorite song on the playlist!
Some days when I don't feel like working out I look at my dog and see her bursting with energy. Taking her to the park, walking or running with her ends up being play time for her and excercise time for me! She usually pushes me too!