Here is an IKEA commercial that was banned in Sweden summarizing (in the most stereotypical manner possible) what the holiday, marking the summer solstice is all about.
Midsummer, the celebration of the summer solstice and the longest day of the year, is a prominent holiday in Sweden. Every June, during the weekend of the summer solstice, people celebrate the holiday by collecting flowers and greens which are used to decorate doorways, make wreaths to be worn or displayed, and to create the maypole (or midsummer pole). The maypole is then erected outside, where people join together to dance and sing around it. Tables are also set up outside and filled with fruit, salads, and various other cold dishes.
How about one more nice cold summer rice dish for this weekend? More Swedish holiday information here.