Double-duty favors?

I like the idea of putting wedding favors to work somehow. I'm having an outdoor wedding and I'd like to give guests something that might be useful or something they will enjoy during the reception, possibly that relates to the outdoor theme, but I'm a little stumped for ideas. It's a summer wedding, so possibly fans or something of that sort. I'd love to hear about what other people have come up or what you've seen that's worked!

Found some interesting ideas here: http://www.bluecollarbride.com/out-of-the-trinket-box-favors/