sipoff
The time at which the first sip is taken: when you begin drinking. Analogous to Tipoff for most sporting events. Implies that the feats that will take place after this time are athletic and in some cases, competitive. Also calls to mind blastoff for space shuttles. Epic.
Guy 1: "What times the party tonight?"
Guy 2: "Sipoff is at 8 pm, should be poppin at around 9:30"
"Sipoff in t-minus 25 minutes."
"3, 2, 1, SIPOFF!!!"
Guy 2: "Sipoff is at 8 pm, should be poppin at around 9:30"
"Sipoff in t-minus 25 minutes."
"3, 2, 1, SIPOFF!!!"