1. A party where there is no drugs or alcohol involved.
2. Being sober for a certain amount of time after having been under the influence for an extended amount of time.
1. I went to a college party expecting to get wasted but it turns out it was a total soberfest.
2. A-"Hey man, you going to head with us to Oktoberfest?"
J-"Nah bro, since my DUI its nothing but going to be nothing but soberfest till this gets cleared up."