Humor blogs CAN make good money from adsense; but it's dependent on TWO factors:

1. Keyword profitability
2. Incoming Traffic

Now, I'm sure you know with Google Adsense, advertisers will bid a certain amount dependent on the keyword and the number of competitors for that keyword. So if anything, make sure that you use mostly BASIC keywords on your site...like 'joke' or 'humor' or 'funny'...only because they're so broad.

The broader the keyword, the more competition. The more competition there is, the more someone's gonna pay to be that 'top dog' for that keyword.

Include your broad keywords in your <title> tag, and try to use it in a <h1> tag if anything. Also remember to try and use the keyword(s) in about 2-3% of the document for good (and believable) keyword density. That way, Google will bless you, and not penalize you for excessive keyword usage, thinking you're trying to 'play' their system.

Now, as far as traffic is concerned...you have a humor blog. The best places to advertise a humor blog is where people go LOOKING for your content...primarily search engines.

Use Google's Adword service if you wanna put a paid ad in the Google searches for your keyword(s). Otherwise...try to get as many other websites to link to yours as possible. There are many ways in which you can do this, such as leaving a link to your site in forum signatures, social network profiles, in comments on other people's blogs...

And since it's a blog...take the RSS feed for it and submit it to as many RSS/blog directories as humanly possible. When each directory picks up your RSS feed, they'll include in in their index of sites, and that ultimately scores you a back link. Yes, RSS feeds carry your website's hyperlink...so if another site uses your RSS feed from your humor blog...that's a link, buddy!

Those are just some tips to help you make good money with Google Adsense from a humor blog.