The US men's and women's basketball teams won opening games easily. There have been some surprises in men's basketball as Croatia stunned Spain while Australia upset France. Australia's women struggled to beat Turkey.
The US women's soccer team got off to a 2-0 start, advancing to the next round.
Katie Ledecky was dominant in setting and world record in winning a gold Sunday night.
There have been other surprising results. Tennis has seen several shocks, including men's number one Novak Djokovic losing to Juan Martin delPotro of Argentina. Venus Williams was eliminated in singles and doubles.
The games will be in the headlines for the next two weeks, enjoy!