Pullups aren't lifting weights, but they have their purpose. If you're looking for an interesting approach to fitness, go check out the Crossfit workouts on their website. I've been doing them lately, and they're pretty damn effective.
In the last week, I've lost 2 lbs!! I've got my sugar, I've begun walking at work, and I do some toning exercises using my own weight for resistance, also while at work. I've had to be careful of my legs though. I fell last spring and now my right thigh will get sore or tense(which also hurts), and it's prone to cramps in the inner thigh. But 2 lbs! It's something anyway.