Earning money on the side

What do you do to earn money on the side? Me, I'm currently an enlisted Navy man (soon to be commissioned) and a college student (long story, but the Navy made me an offer I couldn't refuse). The take-home pay is good, but sometimes it's nice to stretch the budget by adding to the income side, rather than trying to further shrink the outgo side. So, I'm thinking of what I can do to earn a little more income.

A discussion on this very topic at FatWallet.com gave me a few great ideas. Here are some of the ones I plan on implementing:

• eBay sales: get rid of the stuff that I haven't used in over a year. Whatever isn't suited to selling on eBay will get sold at a garage sale in a few weeks.
• Website: I'm planning on starting a great website in a few weeks, when I have the seed money. I'll grow it organically by reinvesting whatever it makes. It would be worthwhile if it made a $200-300 per month, and outstanding if it makes more than that. More on that when it happens.
• 0% balance transfers: A really neat idea, I think, where you take those 0% balance transfer checks that come with a new credit card and deposit them in a high-interest savings account
• Computer "tune-ups": Get a really good antivirus program, maybe McAfee, and charge an hourly fee for fixing people's computers. Hey, I might even get good at it. Also, since I'm not afraid to open up a computer case, I could do hardware upgrades. Once I get into the swing of it, I could develop a custom CD with that automatically runs all the necessary steps to purge the viruses and spyware from the computer. Knowledge is power, and having a friend who's a computer science major doesn't hurt, either.
• Chores around the house: I'm not afraid to break a sweat, and I know how to do basic repairs. This would include stuff like lawn mowing, cleaning gutters, replacing broken electrical outlets, etc. I could position myself as a handyman for hire at an hourly rate. I don't know if any of this requires a license, but I will find out first.
• Surveys/Mystery Shopping: Okay, I'm a guy, so shopping isn't really my thing…but getting stuff for "free" is definitely my thing. If you check out Volition.com, you'll find probably a hundred companies or more that actually hire mystery shoppers. Apparently, all those ads that you see requiring that you pay a fee to become a mystery shopper are ripoffs. I have signed up for a couple of companies so far, and will continue to sign up for more companies. A note: you might want to get certified as a mystery shopper, since it will probably help you get more shopping assignments. Most of the sites have a link to the association that does the certification.
• Tutoring: What can I say, I love to teach. I am in the process of filling out a tedious application for Tutor.com. They put learners and teachers together in an online medium, and the pay is at least $20 per hour. Awesome!

What do I hope to do with this money? Oddly, I can't really say. My needs are being met with our current income. I'm not high maintenance. I guess it's my (admittedly nerdy) way of having fun, by seeing how much I can earn and save.