Here's a quick way for earning money: WidgetBucks

Here's another interesting ad network, it's called WidgetBucks. Like most other ad networks they focuse on PPC (payperclick), CPM (cost per thousand Impressions) and there's even a refferal program. The PPC works when people from the US or Canada click on your widgets, if someone out of the US or Canada sees one of your CPM ads you will get paid. The sign-up is really basic, you have to fill in a form with all the needed information sitename, address, ...
Then your site will be reviewed, and accepted when they meet the Widgetbuck standards. They do this to keep their 'network quality high' so it could happen that your site won't be accepted.

Payments are sent by Paypal or by check. They'll pay you 45 days after the end of each month, but they will only pay you when you earned 50$. As I've mentioned before they pay you with PayPal or checks, you can choose one of them. They used to pay 20$ bucks for joining, but I don't think they do that anymore. So, now over to the referral program, when you reffer a user to WidgetBucks you'll get 5% referral fee for example if someone makes a 100$ bucks you'll get 50$. It's up to you if you want to use it or not. There's no limit on the number of Widgets so you can fill up your blog with as much widgets as you want (muahahahah). Then there's one little thing I want to talk you about concerning WidgetBucks, and that's the MerchSense algorithm engine. From what I've read it detects all of the content on your blog, and gives you more relevant products. You could compare it with the Adsense crawler.