Snoop Dogg's stoner flick Grow House drops today. (4/20)

In an act of promotional genius, Snoop and the cast -- which includes Xzibit and Lil Duval -- smoked so much weed during a round of interviews at the W in LA that they set off the hotel's fire alarms and caused a mass evacuation.

TMZ reports that the hotel staff looked pissed, but that Snoop and friends were totally chilled out during the evacuation.

Here's a trailer for the movie: