A night where a group of friends get absolutely blitzed together.
The drinking itinerary would generally begin with beer and move on to store brand whiskey. There does not need to be a reason for a suicide night, but it will usually occur after a member of the group has split up with his or her partner.
Suicide Nights can occur with only one person in attendance, though, this is generally confused with alcoholism.
"Dude, shit's getting heavy. Suicide Night on Friday?"