Well, I haven't been on a bicycle since falling off one years ago and breaking my wrist. But I have heard of the Tour de France; just don't know a lot about it.
It is one of the most famous bicycle races in the world that takes place every year mostly in France but it also crosses into neighboring countries.
Hmm, I thought it was only in France. When did the race first take place?
The first race was organized in 1903 to increase newspaper sales of all things.  But it has grown quite a bit since then.
That's quite funny actually! It's certainly extremely popular nowadays. Which is the most successful country to compete?
It is extremely popular.  I am actually not sure which country historically has done best in it, but in recent years the US has done pretty well, although they have been found to have cheated.  It is a tough race though so to do well over the whole 3 week time frame it requires a ton of endurance.
It must be very tough to sustain such a level of competitiveness for three weeks. Didn't Lance Armstrong get convicted of cheating - drugs I think?
Yeah he was found to have been doping after denying it for years.  He was suspected for a lot of years though.  In 2006 the launched an official investigation and found him out. 
That's horrible. I'm glad he got caught. Man should be ashamed of himself.
He really should be.  I think a ton of people do it, though.  There have been allegations of doping at the Tour de France ever since it started in 1903!