A blood donation drive held outside the event of Comiket 83 are giving away anime poster as long as you donate blood. This is to solve the lack of blood at blood bank for the coming new year. The anime poster features Magical Girl Lyrical Nanoha The Movie 2nd A and other posters.
However, one of them who received the anime poster after donating blood sold the poster at Yahoo auction for over 27,000 yen. So basically, you just earn 27,000 yen from giving away your blood.