The big yellow-and-pink words "To Do" that turned up Sunday night on the corner of 6th Street and First Avenue are, interestingly enough, just that: to-do lists. The public-art collective Illegal Art installed some 3,744 three-inch-by-three-inch Post-its on two street-level billboards, and passersby are encouraged to write their own to-do lists on the stickies. (Illegal Art collects the lists and replenishes the Post-its each day.) So what do New Yorkers need to do? "E-mail Vinnie." "Eat gummy bears." "Nap." "Samba." And a lot, apparently, need to "Call my mom." —Matthew Fishbane