Dumbbells Met? C'mon mang, don't be that guy - we all hate that guy.
For simple health Mo, situps won't get you far. Go for pushups and cardio, that's it. For getting tank you'd needa lift - gym it, basically. Not gonna happen if you don't have free time. Shass has been bugging me to exercise with her but as I don't really have the time I just help her do crunches and say "yea good job" so I don't have to do anything. But I still do cardio, that shits good for you man - can't be too skinny though.
The thread on **** was by Gavin, I think.