Wonderopolis Wonders is a wonderful site for both teachers and students. You can learn really interesting things everyday and get a link to a lessonplan on the topic.
The site explains the way everyday things come about, such as Who created frozen pizza?, Why are there dimples on a golf ball?, How does a species become endangered?, Who invented dental floss?, and on and on up to 154 lesson to date. You can view a list of all the lessons by clicking on the tag 'Wonders'.
At the bottom of each explanation there's usually a link to an online lesson where the topic can be studied more in detail.
The wonders are also accompanied by a short video in which we usually watch a domestic family scene where the wonder is somehow touched on.
H/T to A Journey in TEFL