It might happen that you are to lazy to drive to the gym or the weather is giving you a hard time like the winter in Europe and parts of the US right now. So what to do? You don’t have a full equipped gym in your one room apartment and no barbells either.
There is no excuse to skip your workout.
There are more then enough good body-weight exercises that are can give you a good workout.
Lets start with some Push-ups. They will train you chest, shoulder and arms. Start with 4 sets a 10-12 reps. You can set a higher goal and maybe try to do One Arm Push-ups after a while. Another idea can be Handstand Push-ups.
View exercise here.
You should also try to flex hard and hold it. Between your sets take some time to stretch. You might reduce the time between sets and maybe look around for some thinks that you can use as weights, e.g. a bucket of protein.
And as always: “Always use proper form while exercising!” No only in the gym also at home.
Next on the list are triceps dips. Take a chair and do your dips.
For your back do Chin-ups or Pull-ups on a door frame. Be careful and first check if your door frame is stable enough.
Legs: Do some Squats. Again 4 sets with 10-12 reps will train you very well. Or try One Leg Squats. Also you can do Lateral Step-ups. For the calves do Calf Raises.
Abs: Do Situps and Crunches.
There are plenty of other exercises. As always I recommend http://www.exrx.net/Lists/Directory.html for an overview and the correct technique.
And please make sure that you train safe.
If you know more useful home workout exercises please feel free to comment.