OpenDNS is a free service you can set up to block adult websites on every device that connects to your wireless network (including mobile devices). If you want the ability to track time spent on specific websites (gaming sites, Facebook etc.), you can get their VIP plan for $20 a year.
OpenDNS sounds really techie, but it’s really not that difficult to set up. Their instructions are very clear and easy to follow. You just need to know the model and brand of your router to get started. To sign up, visit: