And has it ever been done where the victors were so out numbered? i.e. Hannibal: ~25K, Rome: ~90K. Losses on the Roman side were ~70K.
The maneuver you are referring to is called the 'double-envelopment' or a pincer attack. It has been a common tactic throughout history, particularly in those armies that feature high mobility, ranging from the Turks and Mongols to the Germans in WW2. The specific method of Hannibal's double-envelopment, that is, a retreating centre with strong wings that draws the enemy into the pincer rather than forcing it, is a pretty uncommon military tactic. Most often the tactic is used to push the enemy army wings away and then surround it (often this is done by cavalry, hence the 'mobile army' part) while the centre holds the line. In Hannibal's case he drew the Romans in. The arguable similar situation in modern times I can think of would be the Caucus campaign on the Eastern Front in WW2, specifically the envelopment of the Heer's Army Group B. Keep in mind though, this is on a much grander scale than Hannibal's battle.
The Battle of Cowpens in the American Revolutionary war is an example. The numbers were closer to even, but much of the American force was unreliable militia units.
The typical behavior of inexperienced militia is to flee, so Daniel Morgan positioned them in the front line and told them that after the second volley they should run around to behind the hill. The British charged up the hill only to find a second and third line of veterans that had been hidden. The original militia line regrouped and circled in from the right and the American cavalry from the left.
It didn't help that the British had only slept 4 hours in two days and had run out of food.
Soviet offensive at Stalingrad -Operatsiya "Uran" was planned and executed as "almost classic Cannae".
There were non-classic variations, when one of pincer is weaker on purpose or there's auxiliary attack at the center.
Source
Russian - fine map of Stalingrad offensive, including northern flank. November 19- December 11 (pink colored). Note that at Northern flank there is an example of "non-classic Cannae", with asymmetric pincers and central assault. "Almost" part comes from south flank, where part of attacking forces was diverted to drive outer rim of encirclement as far as possible (to Kotel'nikovo).
