Which sport / activity for toning?

[EB89]

I'd like to do a bit of toning up, weightlifting would be the obvious thing to do but I've done it before for a few months and don't really enjoy it. I play Squash and badminton, as a result the upper right hand side of my body has decent definition, but the left side is weak.

Any suggestions for sports I can do that will help tone up? So far wall climbing and swimming come to mind.
For reference, I can't really do a high protein diet - only have one kidney.

[taaffy]

Rowing ..

[Hoofy]

Indoor climbing is convenient. And fun.

[Liokault]

Buy a punch bag.