What is advent? I thought it was just marketing to sell advent calendars, but I started working for a church and they changed their table linens and have special services???
Advent is the liturgical season right before Christmas to help us anticipate the birth of Christ, but also reminds us that we're still waiting for his return. It is also the start of the new year for Roman Catholics and other Christians that use our calendar.
It has gotten a bit consumerist nowadays. But that's all it is.