This should happen on physical cards. If they're handed out for free, it's within the CAH license, and it even shouldn't be hard to do it in such a way that it's immune to the license.
BTW, I'm a fan of having the actual fill-in-the-blanks somewhere in the deck - hooray groanworthy literalism!
(This post won't make much sense if you don't know about the game Cards Against Humanity. Fortunately it has a web site. If you know the game Apples to Apples, well, CAH's gameplay is almost identical to Apples to Apples ... but the cards range from snarky to perverted to shockingly un-PC.)
After the LW meetup in Mountain View yesterday, the idea came up of a Less Wrong expansion set for Cards Against Humanity ... with a roughly Shit Rationalists Say theme, with a little help from Eliezer Yudkowsky Facts. Regardless of whether this ever happens, we felt the need to share the pain with the rest of the community.
These are meant to be mixed with the standard deck. Hence, the completed phrase "That which can be destroyed by being a motherfucking sorceror should be" is a clearly winning combination, as is "Why am I sticky? Grass-fed butter."
Black cards: