Or maybe "can" is a better work... in projects! Here are soe ideas:
Mix crochet and knitting in the same project: http://www.bellaonline.com/articles/art175109.asp/zzz
The mittens I usually wear are crochet with a knit ribbing cuff. I made 3 pairs (The pair for younger daughter is severely ruffled)
I got a nice book on edgings for Christmas. I'm still looking for a good project to apply them to.