We've discussed before on this site the controversy over China's hosting this year's Olympics. Recently there's been a lot of talk in the US and elsewhere about boycotting the Beijing games.
The problem with these boycotts is that they come at enormous cost to the athletes themselves. The intense training and short window of opportunity for athletes means that a boycott can effectively derail their life's efforts up to that point. Recently Canadian athletes spoke out against such a boycott - including some who are still pained by their country's boycotting of the 1980 Moscow Olympics over the Soviet invasion of Afghanistan. This article from the SF Chronicle describes the fate of US athletes who missed their chance because of the 1980 boycott - although it goes too far in the other direction in overestimating the ability of the Olympics to change a host country for the better.
"If there is one thing more punitive for a repressive regime than an Olympic boycott, it is the Olympic spotlight. Adolf Hitler's twisted vision of Aryan superiority was shattered by the four-gold performance of Jesse Owens, an African American, in the 1936 Berlin Games. "
... leading Hitler, of course, to see the error of his ways and resulting in the peaceful, willing dissolution of the Nazi regime.
If ordinary Americans are upset about China's human rights practices and want to express their disapproval, here's an idea: instead of outsourcing the sacrifice to some track runners and swimmers, how about boycotting watching the games instead?
UPDATE: Clinton suggests, maybe just the Opening Ceremony (found on TheBigLead)