OK, baseball, football, basketball, hockey, tennis, swimming, sledding, skiing, track and field, bicycling, rugby, lacrosse, soccer, boxing, skating, rowing, fencing, gymnastics, weightlifting (duh), wrestling, volleyball - all these are out. Even table tennis and badminton are probably on the list of steroids-could-help-you sports, if you are one of the serious, non-back yard types.
And I can't say I think golf, darts, curling, shuffleboard, bowling, shooting, sailing, polo, riding and other such games and pastimes really count as sports, even if your conditioning is superb (and maybe steroids would help you after all). I guess the latter sorts fall in with racing cars, which certainly requires mind-boggling conditioning but isn't really a "sport" either, at least in the Platonic sense I have in mind.
So what's that leave?
Archery? No, alas, even bows and arrows have their troubles: Mark Hainline was busted (for refusing a test) in 2005. Jai alai? I don't think so.
I must be missing something good.