A lottery game is a game like
http://warlight.net/MultiPlayer?GameID=5354536.
Basically, the idea behind these kinds of games is to create a game where the winner is determined wholly by chance to ensure a rapid gaining of points to gain higher levels and, consequently, unlock new features.
The problem with these games are that they are viewed as not "real" games as there is no amount of skill involved, they exploit a loophole in the point/level system, they can be easily used to create abusive templates, and as it takes a very large amount of points to level up to the highest levels, they are created a ludicrous amount of times, clogging up the open game tab.