Here is what I do to keep in shape in my room.
I go outside and run to get basic fitness but to tone the muscles with the least effort, here is what I do:
I have an exercise mat on the floor. This is comprised of 3 sections of spongy plastic material that is good to do sit ups on. It makes a mat of about 2 feet wide by 6 feet long.
The other equipment is a pair of dumbbells. These have a selection of weight discs that are easy to change.
So here are the exercises:
Do some rotations of the joints to warm up.
Grab the dumbbells. Stand up straight looking ahead.
Now, do smooth bicep curls alternating between arms to a total of 30 reps to give each arm 15 reps of motion. Move the bicep muscle in a smooth controlled way through the full range of motion.
Next, lift the dumbbells above your shoulders with the arms bent, ready to push them vertically upwards. You are still stood up straight.
Now, smoothly move the weights up and down vertically through the full range of motion of your shoulder joints. Do 15 reps of this exercise.
Now put the weights down.
Warm up your chest muscles with some in and out movements of your arms in the horizontal plane.
Now get on the mat and into a press up position. Place hands just outside your shoulder position and keep your back very straight with no sag in your mid section. Keep your head horizontal too without bending your neck.
Now pump out 10 reps of press ups where your nose just touches the mat. Keep your body rigid and straight at all times. Smoothly pump out these reps without dramatics and focus on the power that you are going to get in your muscles and the resultant ripped body shape. This is the hardest exercise here.
Once this is over, get on your back and work your stomach.
Put your hands against your ears and bend your knees at 90 degrees. Now raise your back off the floor. Torture your stomach with pulses and 45 degree lifts. Also raise off the floor, hold and twist side to side. Just punish that fat around you waist.
Next relax for a few seconds, stand up and repeat for 2 more sets.
For the next 2 sets you can reduce reps from 15 to 12 then 10.
The above routine is tough enough to kick your body into shape and takes only around 10 minutes so you have no excuses!
If your muscles feel tired the next day, have a recovery day in between exercises.