In the evenings, while I watch tv, I like to earn a few extra dollars at the same time. If I'm watching something that doesn't require much concentration (most shows fit this criteria) I can easily do two things at once.
One thing I'll do is click on the ads at "pay to click" sites. This only pays a penny or two for each ad, but it adds up, and doesn't take much time, since I do it while I'm watching the tube. Some of the sites only pay a fraction of a penny per ad, so I skip those. I find them to be a waste of time. Some of the sites I like, that I have actually been paid by, are http://www.clixsense.com/, http://paidthefastest.com/members/register.php?ref=kdfree (this one lets you cash out to paypal after earning only $1), http://wordlinx.com/?r=286337, http://www.logitraffic.com/index.php?ref_id=15293, http://www2.quickrewards.net/?r=kdfree. Some of the sites I get a referral, so if you use the links I provide to sign up, I will get credit for your clicks too. If you have any friends who are interested, you can have them sign up under you and you will get credit for a percentage of their clicks as well. It only takes a few minutes to sign up for each site, and will only take you a couple minutes each day to click on the ads. Some sites offer a "premium" account which you have to pay for. I never do this. I just sign up for the free, standard account. One word of caution: make sure you have active anti-virus software on your computer. The sites don't guarantee that one of the ads from their advertisers might not have a virus or malware. I have never had any problems, but make sure your virus software is up to date just to be safe.
Another double-tasking activity of mine is performing short tasks on http://www.mturk.com/. Tasks pay anywhere from a few cents to $20 or more. Tasks can be surveys, audio transcription, tagging photos with appropriate tags, behavioral studies submitted by universities, all sorts of interesting things. I personally don't usually bother with hits that pay under 25 cents for a few minutes work. Before you accept a hit, it will tell you about how long it should take. If you start a hit and find that you can't do it, you can return the hit for someone else to work on, but don't do this too often as it will affect your rating on the site. There is a record of your earnings when you log in to amazon.com, and you can use them there to purchase whatever you want. There is also a way to have the funds transferred to your bank account, although I have not done this.
I also like to enter contests while I am in couch potato mode. It is free and easy to enter most contests online, and occasionally I win! I like the ones at Woman's Day magazine: http://sweepstakes.womansday.com/, All You magazine: http://www.allyou.com/sweepstakes-giveaways/, and Better Homes and Gardens: http://www.bhg.com/free-stuff/. I also find sweepstakes on these three websites: http://www.online-sweepstakes.com/, http://contests.about.com/ and http://forum.volition.com/forum.asp?FORUM_ID=10. Even if you don't win that often, it's fun daydreaming about all the great vacations and life-altering windfalls you could be the recipient of!
One more view while I earn activity of mine is to take part in the sponsored polls at http://www.toluna.com/. I do the surveys too, but I find I don't qualify for many of them. There are always polls available to earn points. Each poll earns you anywhere from 15 to a couple hundred points, and only takes a few seconds. It might direct you to a survey afterward, depending on your answer, but you don't have to fill it out if you don't want to. You can just direct your browser back to the site and do more polls. It takes 60,000 points to earn a $20 check. I find that I can quickly and easily earn 1,000 points per day, allowing me to cash out for $20 every few months.
I hope this post has given you a few ideas about how you can be entertained for monetary gain! If you have any of your own tips for earning while you veg in front of the tv, please share!