Amateur Radio constests are on-air events hosted by regional or national radio societies and by amateur radio publications. The basic purpose of a contest is normally to make two-way contact with as many other amateur radio stations as possible during the contest period. Most contests occur on weekends and may last from a few hours to 48 hours for a few of the major contests.
Due to the size of my backyard, I don't have room for big antennas. So, my chances of winning a major contest are non-existant, but I will occasionally place high in a regional contest.