The long-simmering conflict between Georgia and Russia over the semi-independent Georgian region of South Ossetia turned into a hot war this week as Russian forces responded to a Georgian attempt to seize the Ossetian capital of Tskhinvali. Georgian President Mikheil Saakashvili was elected in 2004 on a promise to re-institute South Ossetia into his country, and has been nuzzling up to the West, collecting military aid from the U.S. and Israel though his attempts to join NATO were rebuffed. NATO, apparently, wants to box Russia in but doesn't want to take on some ambitious head of state who might start shooting.
It's unclear quite what Saakashvili hopes to achieve with such a grossly lopsided conflict. Perhaps he was banking on more material support from his Western clients but, as much as the current brain trust in Washington is generally unpredictable and loves tweaking Russia, they aren't eager to get involved in a real shooting war. Moscow has been baiting Saakashvili to do what he just did and give them an excuse to forcibly annex South Ossetia and, more pertinently to their goals, perhaps install a pliable puppet government in Tbilisi.
Robert Farley has been covering this story extensively. The Newshoggers and Duck of Minerva each have several posts. Lenin's Tomb and American Leftist provide more background.