I remember that scene!  It's from OVA 13 when 
Washu is betting that Mihoshi will win in the 
fight between Tenchi and Serio (I THINK that's 
the guy's name). ^_^  I'm almost afraid to ask 
what you'd want for it though...

I usually collect BGC OVA cels, but this cel 
would be a nice start for a Tenchi collection ;)