#1
This has probably been asked a million times, but I can't seem to find anything.
I have to improvise a solo on a concert tommorow on a jazz piece. The part I'm supposed to improvise on is a G blues, so I'm pretty much using notes in the G pentatonic, however, are there any other scales I could use? I know I saw this somewhere, but I think it should be the G mixolydian (which starts on D) and I don't know what else, but give me a list of scale names and I'll figure it out.
#2
G minor pentatonic also has its times. There's really not much to blues.

I'd suggest you study some blues and take some licks and scales that you discover, instead of just playing notes inside of a scale. I tell you, playing patterns is the most confining thing ever.
Only play what you hear. If you don’t hear anything, don’t play anything.
-Chick Corea
#3
I wouldn't try using new scales for a concert tomorrow! Practice what you know - get yourself some backing tracks, listen to them, try singing a solo over them, then try playing bits of that over it on your guitar. Practice improvising as much as you can before the concert - preferably over teh same song - til it starts to take shape in your head. Waiting til the day before teh concert isn't giving yourself much of a chance though :S