Counts the pens. News reports said that the president signed health care reform into law with either 20 (The New York Times) or 22 pens (Everyone else). The White House posted the ceremony at YouTube so you can count for yourself, starting at 25 minutes into the 27 minute ceremony, when Mr. Obama quips, "This is going to take a little while."
The pens hits the page 22 times. But there's only 11 letters in "Barack Obama" (add seven more for his middle name) so he's clearly having to sign partial letters.
There's a long history to this practice, which creates historical artifacts and gifts. President Kennedy used his middle name and flourishes to stretch things out. President Lyndon Johnson used 75 pens to sign the Civil Rights Act, with one of the first going to Martin Luther King, Jr., and then key legislators. Here's a list of who'll get the 22 pens. (New York Times, Los Angeles Times, TIME, Washington Post)