In this puzzle, you were asked to find twenty-three answers and then to group them in three categories, providing the one missing answer for a total of eight answers per category.  I was quite pleased with this puzzle.  It seemed like the kind of puzzle I'd enjoy doing if someone else wrote it.

First, I'll give the answers to the questions.

1. _________ of the above
   None
   
2. 11th prime number
   31
   
3. ZIP 60033
   Harvard (Illinois)
   
4. dotdotdot
   S
   
5. ET’s buddy
   Elliot
   
6. Familiar name of William Cavendish’s third wife
   Bess
   
7. First name of “Captain” seen in several Cyndi Lauper videos
   Lou (Albano)
   
8. First name of actor who played Ms. DiPesto’s suitor
   Curtis (Armstrong)
   
9. 
   1972
   
10. First name of the person who averaged 14.3 points per game in 21 games in the 2008 NBA post-season
    Lamar (Odom)
    
11. Furry guy whose original name was Woof-Woof
    Barkley.  I like Woof-Woof better!
    
12. Hexadecimal 21
    33
    
13. Jersey number of the person who rushed for 191 yards in SuperBowl XVIII
    32
    
14. Judy Blume title character who does bust-enlargement calisthenics
    Margaret
15. 
    C
    
16. Last name of former MLB manager known as “Scrap-Iron”
    Garner (Phil)
    
17. Last name of the actor who played this guy in two live-action films
    
    Stanford
    
18. Ms. Rigby of song
    Eleanor
    
19. N 51.54°, W 106.04°
    Allan (Saskatchewan)
    
20. The sunshine vitamin
    D
    
21. University of Chicago calls this neighborhood home (two words)
    Hyde Park
    
22. x when x+2y=1955 and 5x-1103y=4210
    1945
    
23. Year of Jeopardy!'s debut.
    1964

 I kinda thought Hyde Park would be one of the major giveaways, or maybe Eleanor and Bess.

The first (and only!) response was from Malia, who got them all correct for 27 points.  Here's how she grouped the answers.

HERBERT CLARKE HOOVER

president =  31
middle initial = C
born = West Branch
VP = Curtis
wife = Lou
child = Allan
college = Stanford
died = 1964


FRANKLIN DELANO ROOSEVELT

president = 32
middle initial = D
born = Hyde Park
VP = Garner
wife = Eleanor
child = Elliot
college = Harvard
died = 1945


HARRY S TRUMAN

president = 33
middle initial = S
born  = Lamar
VP = Barkley
wife = Bess
child = Margaret
college = none
died = 1972

As you can see, the missing answer is West Branch.  Nice job, Malia!