I've been exercising in my room using only my father's pair of dumbbells (I started with 5 kg and ended up with 8 kg, I didn't feel like doing more than that) and a towel on the floor since I was 16, even in summer (using a fan and usually starting past 18:30 h). I started doing approx 45 minutes of exercise, now it's close to an hour, every two days, full body. I've been varying it a bit during the years, and now I usually do other stuff since I started going to the gym (mostly swimming). I'm not looking for anything in particular besides feeling good and gaining some muscle. I don't care much about any diet besides not eating pastries or too many sweets. So this is my routine now when I do it at home, maybe instead of full body I do only upper or lower body:
1) Some 10s stretching per group of muscles as warming. Also, 15s of rest between series and drinking some water between different exercises.
We start standing, making use of my bed or a flat vertical surface like my wardrobe if necessary:
2) 5 series of 24 weight uplifts (switching arms until a total of 24, so 12 per arm) for biceps.
3) 5 series of 24 weight uplifts (12 per arm, then switching arms) for triceps.
4) 5 series of 12 and 6 weight uplifts (both arms at the same time, alternating one series of 12 with 1 kg with one series of 6 with 8 kg) for deltoids.
5) 6 series of 20 pressing the palms of my hands against each other in front of my chest (the tips of the fingers touching the inner side of the wrists, so not like praying) for pectorals.
Now on the floor:
6) Facing up: 5 series of 20 leg uplifts (switching legs).
7) Facing down: 100s of plank.
8) 100s of left-side plank and then 100s of right-side plank.
9) Facing down: 20 opposite arm and leg uplifts (switching arms and legs).
10) Facing down: 20 torso uplifts.
Now standing up again:
11) 4 series of 20 backside leg uplift (20 per leg, then switching legs, but maybe I should switch for every uplift).
12) 3 series of 20 squats holding an 8 kg dumbbell against my torso.
13) 3 series of 20 standing on tiptoes.
14) Some 15-25s stretching per group of muscles for cooling down.
When I don't exercise at home, but in the gym or outside, or if I don't really feel like exercising at all, I do some of this, depending on what I feel like doing:
a) 1 hour of fast walking in the mountain (like I'm about to lose the train or something, so with lots of energy).
b) 30 min swimming (10 front crawl/freestyle, 10 backstroke, 10 breaststroke, 2 diving).
c) 30 min jogging (usually alternating 8-9 min of jogging with 1-2 minutes of walking to rest a bit).
d) 1-hour walk coming home from work, or just going out for a 1-hour walk.
e) I go to the outdoor gym to do some rowing and using the pull down machine, since I usually get upper back contractions due to my office job.
I don't exercise everyday, I don't even exercise every two days since I started working three years ago, because I just prioritize other things in my life, but I feel like I really need to discipline myself again on exercising. I don't exercise outside only if it rains. If it's cold I just wrap myself up a bit, and if it's hot I do it on early or late hours.