THEME:   none, but I don't know why --- if the grid is not especially demanding of the constructor, it would seem a theme should be offered   
GOOD ONES:   Night time   TENPM [note spelling]   
Game with a disk operating system?   SKEET [the disks are the clay pigeons]   
"Scarborough Fair" quartet   HERBS [I first thought of the singing duo before "parsley, sage, rosemary & thyme"]   
Night sound?   LONGI [had to be SNORE --- wrong!]   
Spread with hands   RANCH [sometimes called "spread" which I think I learned from Zane Grey novels or maybe TV westerns]      
BTW:   Guy giving you a pointer?   UNCLESAM [it's a good one but I think it needs the past tense]   
CES is not English   
Element no. 39   Thought I made a mistake when I wrote 
YTTrium, which I never learned in Chem.      
RATING: 
 
   Three grins = Loved it; Two grins = Enjoyed it; One grin = A bit bland for my taste; One teardrop = Not much fun