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.
Population bottleneck, when a population's size becomes very small very quickly, and the founder effect, when a few individuals in a population colonize a new location that is separate from the old population, are the two main types of genetic drift.