Georgia is a sovereign nation that used to be part of the Soviet Union. There are 2 regions of Georgia which wish to be independent of Georgia. Georgia sent soldiers into these regions as soon as the Olympics started. Russia sent quite a bit of firepower to successfully push the Georgian military out of these regions.

Georgia, which by the way is friendly to the US, probably thought we would come to their assistance. These breakaway regions are friendly to Russia.

It's a simple explanation for a complicated situation. Russia has officially recognized these regions as independent of Georgia. Here's the latest: Russia recognizes breakaway Georgian regions - Yahoo! News