I was thinking the same thing- having some that weren't holidays.
I bet ya all can come up with some super creative themes...
some random ideas from me:
1.a music theme- and include a mix cd with some of your favorite music on it (you would have to make one for each person but would get one from each person PLUS there swap item) the cd part is optional depending on what ya all wanna do.. they are light to ship though;) music inspires creativity in every culture and language.. and you could create something music themed easily no matter your medium... could be open to many possibilities
2. woodland - I am personally obsessed with squirrels and all things woodland and they are trending pretty heavy on etsy still. woodland- think trees, squirrels, foxes, blue skies, racoons, chipmunks, moss, floral, nature themed...
3. weather- this could be fun. anything weather themed- clouds, rain, sunshine, storms, natural disasters.........
4. for him- something for the guys in our lives (this is a challenge for a lot of people and might help people expand ideas for their own shop)
5. twilight- (PLEASE not the movie.. hehe) meaning stars and moons, blacks, sunsets, that kind of thing..
6.I've Never - a swap with items that are not and have never been listed in your shop before... a chance to try out a new media or idea- or to simply show off your many talents. Helps us come up with new ideas and maybe great ideas for the future for our shop as well.
7. local wonders- your items would be themed - loosely or not- around your local region or culture. so everyone's would be a bit different naturally ;)
8. bibliophile - book lovers- literature themed- could be a quote or inspiration from one of your fav books- or more literal.
9. recycle, up-cycle, ecofriendly, etc -
10. geekery - star wars, star trek, doctor who, nerdy stuff, mario and nintendo themed, etc, etc
again these are just some random ideas.
one of the things i would like considered is the time we have to make our items. if we gave people a bit longer from the time we signed up and closed the sign up to the time our items have to be arrived I think it would encourage creativity and people to sign up. since these swaps are not limited to the number of people they could get very large quickly and unexpectedly... and I personally would rather wait a bit longer to get my items and have them be nicer, than rushed. Not saying anyone rushed theirs, but ya all get the idea.
Also I would say that all my ideas are meant to inspire- to be taken literally or less literally- it would be open to the person how to interpret the theme.
Would love to here what ya all think.