Hestasport-Activity Tours (Vegamót, 560 Varmahlíð, Iceland; phone +[354] 453 8383, fax 8384, www.rafting.is) offers whitewater rafting trips in northern Iceland. From May until Mid-July, the region has sunlight 24 hours a day, which allows for rafting at midnight, not to mention a mid-ride stopover for pancakes and hot chocolate with rum.
A 4-hour trip on the West Glacial River includes 1½ to two hours on the river, costs ISK6,500 (near $68), with drysuits, booties, gloves and helmet, and must be arranged in advance.