There are many exercises you can even do without equipment. Push ups, superman's (back extension), and even lunges as I would not leave out your lower body, then get maybe the 2-5kg weights and do tricep press, bicep curl, lateral rais (shoulders) and many more.
Frank, My neighbor whi is a Caption in the LA Fire Department invited me over one day to try out the P90X workout routine. We did the Plyometrics one that day and it was pretty awesome workout. I'm in pretty good shape and was a rower in college. Um that was 20 some years ago though but I wanted to get somewhat close to being in the shape I was. My gym had just closed down and I didn't really like the one we ended up going to but my wife loves taking yoga classes so we ended up there. They did have an erg which I liked. Anyway, I ended up trying the P90X workout for 90 days and it was awesome. The workouts las about an hour with 10 minute warmup and 6 to 7 cool downs and are very diverse in nature which is by design. All you need is a few dumbells and if you can a pull up bar. The workout DVD's cost about $120 and I was unsure of it when I looked into it. But having been able to try it out first. Best value ever. Sounds like it will fit into your financial and time constraints. I've lost 30 lbs and was doing almost 10 pull ups for each set by the end. (I was doing like 1 when I first started) If you work hard, eat right like the program outlines for you, you'll be in awesome shape from a strength, endurance, flexibility, and balance perspective.
I do some sit-ups at night but I'm really constrained with time and fatigue just now. Out the house at 6 on my feet all day and back at 19:30. I was a rower for my college too in 89-92. Let myself go a bit since.
unfortuantely when people wait for time to be available to exercise, it never happens. We have to make time for exercise no matter what even when we are exhausted. Put 20min aside each morning or evening before or after work that you must do.
So where did you row? I rowed at George Mason and then a summer at Bachelors in Philly as a light weight. (I'm not a light weight now but I'm getting back to my 175 rowing weight at Mason)
Niffer is spot on. Life is about balance and if you don't have an hour in a day to yourself to work out than your out of balance. When you take the time to work out you will have more energy throughout the day and be more productive. And eat healthy as well. If your 30 lbs over weight that is DEAD weight your lugging around all day long and don't have the strenght and endurance to do so on top of that.
Take control and do the right thing.