Active.com is a service that allows you to find and participate in sporting events.
At the end of your purchase, you verify the contents of your cart, agree to various terms, and enter your billing information. At this point they display a screen containing fine print. In this fine print is a statement that you are also agreeing to pay for a recurring subscription to “Active Advantage”.
Image source: Mattcuts.com
If you’re not paying attention, you may never realize that you are agreeing to be billed $64.95/year. Although it is possible to opt out, it’s neither clear nor easy to do so. Further details of this dark pattern can be found here. Numerous complaints can also be found on review sites, like this entry on yelp.com.