AdSense
Well, I decided to poke around with the cool new widget system for the WordPress sidebar and I saw some widgets for Google AdSense, and I remembered that I have an account with them from long, long ago! So I log in and see that I earned 17 cents from the month or so that I had on my ancient site, and I thought, "hey! Maybe I should try this again for fun. My site's more popular now, and I get spam comments like you wouldn't believe... Maybe I'll get some money per page load!"
It took me a while to get it to work... I thought maybe the sidebar was stripping javascript but, uhm... I forgot I had AdBlock Plus running, and it was hiding the entire ad to begin with. Yeah... If you ever want to try adding ads, be sure you turn that off!
The ads I might not keep, but they're buried at the bottom of the sidebar, so if it remains distracting, I'll take them off... But I might keep the referral buttons for Firefox and Google Pack. I prefer to use Opera now, but even Firefox is better than Internet Explorer when it comes to rendering pages properly, and Google Pack has Skype and OpenOffice and Google Earth, and those are neat, so I'll probably keep those, too. But, we'll see... I'm just bored... I should probably go read my A+ book. (Except I can't pull myself away from this really neat music, hmm... Such a dilemma.)