Later there were outbreaks in China, Greece, several Latin American and African countries of which Zimbabwe had a good one, too. Before Zimbabwe essentially gave up on having a national currency they were on their fourth "Zimbabwe dollar", and somewhere along the way a banknote of 100,000,000,000,000 Zimbabwe dollars was issued, which is a popular item on eBay.
But the record is still Hungary after WW2. The amazing thing there is the speed with which everything happened. On May 1, 1945 the first postwar rates were introduced and the inland letter rate was set at 1 Pengö. By early January 1946 it was 600 Pengö, which is impressive but after that, things just became surreal. What was particularly interesting was the Hungarian government's attempts to keep renaming the currency. So the Pengö was followed by the ezerPengö (1000 Pengö), the MilPengö (1,000,000 Pengö), the Milliard Pengö (1,000,000,000 Pengö) and the BilPengö (1,000,000,000,000 Pengö). By now we're in early July 1946. That's right, the letter rate went up by a factor of about 60 billion in 6 months! July 1946 then just went further into funny numbers, with the introduction of an adoPengö ("tax-Pengö") not really helping. When the Forint was introduced on 1 August 1946 the stabilization rate deleted TWENTY-NINE ZEROES.
This (second - they had a first run at it post-WW1) Hungarian Hyperinflation is of course very interesting philatelically as well. The Collector's Club of Chicago has published a really nice book on the subject which is available free as an e-book too. Recommended reading!