Robots and Monsters is exactly the sort of charity I like to donate to. From their website:
RobotsAndMonsters.org is a charitable art project that matches goodwill and charitable giving with custom-made commissioned cartoon and pop art.
Although they don't seem to have anyone special on their Supported Cause list right now, last quarter, proceeds from sales / donations went to the EFF, one of my favorite causes. They have supported several other worthy organizations in the past, but orders made in between support sessions go directly towards RobotsandMonsters.org, which is worthwhile in and of itself.