The Lottery is pretty unique. I don't think any other con does it. It's like the pickup circle so there is no limit to the number of people that can participate.The idea is simple: instead of making an intelligent, careful, decision about what you play and who you play with, throw caution to the wind and let the fates decide for you.
The procedure is exactly what it sounds like. Everybody gets together and throws their event badges into a basket. We randomly draw four at a time, read the names (and return the badges) and those people go off and game. What they play is totally up to them.
You may play with people you would have never otherwise gamed with. All the normal social pressures that affect who you decide to play with go straight out the window. And you may try games you would never have otherwise tried, because you happen to be in a group with other people who know about and want to play that game. Or even if you play something familiar, maybe someone else in your group is being exposed to something they would never have considered playing. It’s all in the hands of fate.