Try to sell them in Denmark. Put up ads - the most popular craigslist-style board is guloggratis:
http://www.guloggratis.dk/fritid/rejser-forlystelser/.
Also try the danish ebay / ebay classifieds and the
dba.dk and
qxl.dk markets. Don't expect to get much, though - buying one now for that date is $342.
Should you cancel, expect to be refunded around $64 in taxes.