Mardi Gras-a carnival held in some countries on Shrove Tuesday (the last day before Lent) but especially in New Orleans.
Bottleneck effect is when there's something that either kills the majority of the population or just prevents it from reproducing. This creates genetic drift because the likelihood of gene prominence changing is much higher in a small population. The Founder Effect is a type of Bottleneck effect. It is when a small amount of individuals starts a population usually due to migration.
The Founder Effect also describes a population with a loss in genetic variation, however the cause is not associated a decrease on total population, but in a small part of the original population moving into a new habitat and becoming genetically isolated from the original population.