If you do have bobby pins, by all means use those first!
However, if you meant to get a haircut a month ago and don't have any bobby pins on hand because why on earth would anyone own hair accessories... this is worth a try
Attempt to pick a lock
A quick Google search tells me that this is actually possible. I haven't tried it myself though.
Note: I'm not saying you should pick any locks, just that you could if you so desired.
Make jewelry
Pinterest has some examples that are much fancier than the elementary school paper clip chain bracelets.
However, keep in mind that #pinterestfail is a common phenomenon among many who attempt to replicate Pinterest projects.
Clip papers together. Because they are, y'know, made for that purpose.