2-way cabled vest/cowl - *Inspiration* this one is knit but you could easily crochet this so pull out your favorite scarf pattern and get to crocheting. You may need to adjust the width of the scarf. Once your scarf is long enough, wrap it around yourself and tack the ends to each other then tack the 2 back edges to each other, take it off and sew where you tacked using matching yarn.
Provisionally Casting On With A Crochet Hook | Eskimimi Makes I use this non-provisionally too (just use the working yarn, and don't bother with a chain at the start/end). Makes a great match to the standard knitted bind-off edge.