I have grown red and yellow sweet peppers and some of the leaves are bending themselves right over so you see just the unerside of the leaf.
Do you know why this might be and is it ok
I would take a guess at lack of feeding, but an expert will be along soon.
I'd go for fluctuation of temp... they tend to grow out of it as (if) the summer warms up.. :-\
I would agree with Saddad, mine are doing the same since we got the cooler cloudier weather :(