What about the taxes question in episode 4?
 

I've done everything else, including aranging Sybil's date. How do I get the crowd to boo during the taxes question?

You need a new cue card. You won't find it at the White House.

Head back to Sam & Max's neighborhood... see anything there that would work?

Check out the signs at the back of the alley next to Sybil's.

Go to the wall of posters near Lefty's and click on the posters that say give me all you got then go to the white house, replace the cue card with G.M.A.Y.G and ask Abe about taxes.

1 year, 5 months, 8 days, 22 hours, and 30 minutes between posts. Not the most I've ever seen, but still decidedly impressive.

Ladies an gentleman, here we have the king of the necroposters.
Let us hope his undead army leave our brains alone.