Just as much as you can't develop a full blown application while on the bus, you can't expect incredible results from working out for a few minutes at home. You need to put in some serious effort to see changes. I go four times a week to the gym. I understand that this isn't possible for everyone, but even going just once a week and putting in a solid workout would be better than doing a few situps and pushups every night. Of course, if you are gaining weight, you need to eat less/use more energy. If you want more muscle or more toned muscle, you need to weight train. I'd recommend a three day plan: two days to spend with weights on your entire body, a few sets for each body part, and a third day for some light cardio. Don't forget that with the extra exercise, you might need to eat a little more. Aim for more frequent, but smaller meals.