I'm giving a serious thought about monetizing my blog & games - and I come to think about in-game ads + some sort of link/banner ad combination in the download page.
My blog reaches over 10K unique visits (Google Analytics) which does not include RSS readers. Total number is probably around 20K per month or so.
Anyway - I'm going to start developing a video game that can be downloaded via Internet and played for free. My idea is to update the game in small portions: one week at a time - and I would add more and more details and features over time. The game uses physics engine, so in one update I could add a basketball (and player could throw the ball around the room...) and in one update I would add TV (where he could check ads

) or billiard game (where he could push the balls and play billiard).
I would give the game for free and I could expect to see 10K - 100K downloads (and download page views) monthly.
Ad options:
(1) Would you be interested placing your ad both in the game (permanent slot, like your product could be placed in a texture file and displayed in the television: when player checks out the television and clicks it - he would go to your website. Or - perhaps you could have a .wav or .mp3 audio file and when player listens to music, he would occasionally hear your ad in the radio.)
(2) I could also list all the sponsors in the download page (text link or small 88x31 banner) and perhaps some big rotating ad as well (which would randomly pick one ad).
(3) The last place to put ads would be before the game launches and when the game ends: player would see one big ad of your product (random ad).
(4) Ad listing in game: user could see all ads listed in a newspaper or somewhere and he could click the newspaper and would be forwarded to AD page in the internet.
(5) I could add your ad on GameProducer.net blog (it's ranked around 15000 out of 54 million blogs in Technorati, and has a page rank 5 - I have done maybe about 20-30 link exchanging, but most of the people have linked to the site from their own will and I haven't done any SEO stuff to get the pagerank up - it's gone up 'naturally'

).
Notice: your ad would be located in the game forever, and you even could get some slots totally dedicated to you... like for example there could be a poster in a wall that would display your ad - and no other ads would be seen in that spot.
Part of game to check out: (I'm first going to build a tower building game: player must build as tall tower as possible using boxes)
This requires bit technology savvy person to check out a small demo, but in case you are familiar with .zip files, check out this:
http://www.gameproducer.net/public/demo.zip
Screenshot available as well: (check out the attached demo001.jpg)
Bottom line:
Several ad slots, free constantly update game (to reach those 10-100K downloads per month), ad slots at gameproducer.net.
Would you be interested? What would you be interested to invest on this?