If you're hair isn't quite long enough (or you prefer something a little more subtle) a small scalp plait running along your hair line can look really nice. I've also found it really handy because I'm growing my side fringe out because I'm in a musical in 2 weeks and it can be hidden withing the scalp plait.
I'm all for this - I think it really adds something to an otherwise drab head of hair. Though I hope it's a trend that doesn't become mainstream (and hopefully won't - can't imagine it's easy to do?)
to do it just grab a section from the side, braid and wrap around your head. if you have short hair you may need to frech braid the whole thing (thats where you pull in new bits of hair as you go)...