I started off just doing core exercises ~3 months ago due to being overweight and having occasional back pain. I make sure I do it every morning and keep my pace somewhat quick to have it be a bit of a cardio workup for me as well. Getting up in the morning is really tough for me, but getting in a little workout sometimes I feel pretty good afterwards and throughout the day. Other days it is just normal tired feeling.
My routine is pretty simple and I do it all at home infront of the TV before showering and going to work.
Crunches - this is mostly for back/core strength rather than a snowboard workout. 4 sets straight/forward, 4 sets to the right side, 4 sets to the left side (each set = 25)
Pushups - 3 sets of 10 each - pretty weak here at the moment, but building up. When I started, I could barely manage the first set of 10. Now I'm to the point of thinking about bumping sets up to 12 or 15
Squats - These are what I noticed helped the most when riding. My legs feel stronger and less like jello towards the end of the day. 4 sets of 25 again with these. No weights yet, still doing it with just my body weight.
If any of you other guys are overweight at all and/or have any back pain normally, I would
highly recommend doing core exercises. Generally I'm pretty lazy and I hate mornings, but my back has felt pretty good since I have been working out, so I'm going to keep with it. I feel a bit stronger which is nice and I've lost a little weight as well. Probably not too much, but definitely some - I need to get a scale for reference. All you need is a little motivation and space in a room. I also use a yoga mat which is helpful to cushion the ground which makes the crunches and squats more comfortable.
I honestly don't ever see myself paying for a gym membership or going to the gym with any regularity. My next step is to invest in some free-weights and/or a kettlebell to add some weight resistance to exercises.
Oh, and I work on the 3rd floor, so I no longer take the elevator. Every little bit helps, right?