For the sake of nominating - I just bought the Hal Spacejock series - so I nominate Hal Spacejock #1.
I'm not really a humour reader, but as I just bought these and they're available quite cheaply in ePub or mobi from the author's site and are not geo-restricted in any way this makes them attractive to me. #1 is only $1.99 at the moment.
If you're interested - you can purchase them here:
http://www.spacejock.com.au/index.html
Regards
Caleb