I've found a couple: surveyspot.com and my2cents.com.
If you're OK with making $1 - $2 for 20 minutes of your time you can make a few bucks with them. Occassionally you might get a $5 one.

My experience is much like Pete, did it every now and then for several months, finally requested my payments of $30 and $9 respectively. Hardly worth my time unless I'm really bored.