The Gallic Wars lasted from 58 BC to 51 BC.  It was Julius Caesar vs. the Gallic tribes, with Julius Caesar instigating the battles.  These wars were made up of three particular parts; the campaign against the Helvetii, the war against the Suebi, and the Punitive expeditions. 
The Helvetii were a people who lived on what is now Switzerland.  Because their Northern neighbors invading their borders, the Helvetti began a mass migration, led by a man named Orgetorix.  Orgetorix wanted to take over Gaul, and found two countries that he would join with when the plan was complete.  He was tried in front the Helvetti government, but his conspiracy was denounced.  However, he died shortly after that.  The Helvetti's continued with their plan.  They had to pass through Geneva to continue, but Caesar heard of their plans and blocked the bridge to Geneva.  Caesar stalled the Helvetti's by pretending to ask them to consider an alternative.  After reinforcements got to him, he abandoned his facade and ended up chasing the Helvetti down and defeated them.  The Helvetti were sent back to their homes, and Caesar won more prestige.
In the war against the Suebi, Caesar was asked to split up a conflict between two Germanic tribes, the Aedui and the Arverni.  The Averni had hired the now out-of-control mercenaries taking part in the conflict.  Caesar took out the group that had hired the mercenaries, sending the rest home.
During the Punitive expeditions, the Romans went head to head with the Veneti tribe, who forced the Romans to go to sea to battle.  Although this was not what the Roman's were used to, they defeated the Veneti.  He also led expeditions against the Germans and Britons.  
Vercingetorix was a leader who unified much of Gaul and tried to fight the Roman power.  He was forced to give up in 52 BC.  He was imprisoned, paraded through the streets of Rome, and publicly executed.