I was walking barelegged across a desert-like blue and red plain with sparse vegetation and rocks. There was a sudden sharp pain in my leg. I turned around and saw something out of the corner of my eye. Then it happened again. What was that? Somebody standing off to the side, out of my line of vision, but a friend, called out, "watch out! there's more of them!" And it happened again.
And this time I saw it, a spider about the size of one of those little yap-yap dogs. I gave it a kick and it scuttled away under a rock. But then as I turned around there were three more of them. They were everywhere, for miles. They were fast. And where was my friend? Gone. Aieee! Help! So I realized I was in a dream, and I forced myself to wake up. Sometimes I am able to control what happens in my "lucid dreams," but in this case no immediate solution presented itself (a flood? a helicopter rescue?). I was distracted. Spiders were biting me!
It took me two hours to get back to sleep. (I listened to some more podcasts and updated this post.) This lucid dream reminded me that one of my favorite movies is Richard Linklater's "Waking Life" (2001), which touches on lucid dreaming, so I spent a few minutes this morning looking at The Lucidity Institute and this how-to wiki.
Some people don't remember their dreams (I usually do, for a while), and some can't influence them (I can, sometimes). To remember them, write them down as soon as you wake up. To influence them, try writing down some ideas before you go to sleep. To control them, the first step is to be aware you are dreaming. If you are in a weird situation and you think it might be a dream, try to read some writing or look at a clock. If you can't make out the symbols, you're probably dreaming and with practice you can learn to change the situation.
But let me reiterate: This is hard to do if a) you are in a desert without clocks or books around, and b) you are getting bitten by giant spiders.