I just started a new knitting project: a scarf in rainbow-coloured variegated wool. I like to use circular needles whenever possible, because I tend to drop things - and trust me, given the opportunity to drop my straight needles, I will drop them with discouraging frequency.The only problem with circular needles is that, when they're stored in their original packages, they take on the tight curve that they've been stored in, and when you go to use them, the flexible part becomes very wayward.
This morning I decided to remedy the situation by ironing my needle. Applied with care, heat will relax the plastic and encourage it to take a new shape.
Find the full instructions for how to straighten a circular knitting needle in this Facebook photo album (you don't have to be a Facebook member to view the album).