A simple but effective exercise for developing all round strength and stamina is the Farmer's Walk. All you need is a set of dumbells, kettlebells or cinder blocks.
1. Take both dumbells in hand.
2. Hold them above your head.
3. Walk around your block.
Or here is a variation
Just take the dumbells, one in each hand, and walk around your block at a brisk pace or up and down a steep incline.
The heavier the dumbell/kettlebells/objects the better off you'll be. If you have to set the dumbells down and rest that's great because it means you have to pick them back up again thereby executing a squat, cleaning type of action.
You can also perform bicep curls as you walk or military presses.