I really like Call Centre HQ because the majority of my work background is in call centres and so I was easily able to jump into a position like this. The way it works is you are given assigned 'mystery call centre shopper' leads, where you call up the particular call centres and go through the motions like you would calling anywhere. You need to review things such as the operators friendliness, greeting, their communication skills, whether or not you received the answers to your questions and if there was any follow-up.
Once you have completed the call you fill out an evaluation form for the company or call centre and email it to them. As long as you take notes in the call as to what you want to write and are detailed in the pros and cons of the call, you can usually fill out a form pretty detailed. Each call must be a minimum of 6 minutes and you need to keep track of the number you called from or used during the call. The company pays pretty fast and it's $5 for every evaluation, usually arriving via Paypal within 48 hours at the latest. The reason why I like this job so much is that you can schedule your calls around your own time and when the call centre itself is open. You also don't have to worry about a disruptive background noise such as pets, kids or any other distractions because you want to appear as a normal everyday caller.
I would recommend this to someone who is looking for something different from the typical at-home jobs available, but you need to be quick on your feet and should have call centre experience so you can anticipate the types of conversations you can get into and how to get out of them without blowing your cover.