To Guy (who's sister was in the barroom scene in Buckaroo Bonzai):
 
Speaking of the barroom (nightclub?) scene--when Penny (mis)fires her gun,
Buckaroo's entourage's reaction is hilarious--they all pull their guns as if
they are the Secret Service.  Not the reaction you expect and it is strangely
humorous (a two word description that fits the entire film)
 
Re: the watermelon--perhaps it was meant to segue to the sequel?