If you have a hard time motivating yourself to work out, here's a little trick. Every time you exercise, whether you go for a walk, hike with a friend, or hit the gym, mark that day with a big X in your calendar. It'll give you a quick general overview of how often you've been working out that month so far, plus it'll serve as a visual reminder of how long it's been since you last worked out.
If giant Xs don't do it for you, then draw a smiley face, or a heart, or a little flower. You can even use different shapes or colors to show what kind of activity you did each day. It's definitely a great feeling when you can look back in your calendar and see all those days marked off. For even more motivation, reward yourself every time you get 20 Xs.