11. Least evident world champion

Iser Koeperman (Soviet-Union, nowadays United States of America) in 1974. He didn't need to play because there was no opponent.

12. Oldest (10x10) draughts club that still exists

Constant, Rotterdam, The Netherlands, founded in 1899.

13. World record playing draughts simultaneously

Jannes van der Wal, The Netherlands (former world champion), played against 225 on 16-17 July 1987. Only 14 draws and 4 losses.

But on 2 September 2006 in Diessen (Netherlands Anton van Berkel improved this record.

Van Berkel scored against 249 players 81%, just above the obligatorily 80%.

14.  World record playing draughts simultaneously with a roulation system.

Harm Wiersma, The Netherlands, in 1983 in Amsterdam. 

He played 428 games. Only 50 draws and 5 losses.

15. World record playing draughts simultaneously in a blind session

Ton Sijbrands played on 24-25 of September 2009 in the Olympic Stadium of Amsterdam 'blind' against 28 opponents. His score of 76,8 % was above the limit of the FMJD (70%). Sijbrands took 41 hours for this session. 
See also nr. 77 and 78 (Italian draughts and checkers)!

16. World record playing draughts and chess simultaneously in a combination

Jannes van der Wal on 23 June 1996 in Stadskanaal against 85 spelers. He lossed 2 games against a draughts player and 2 games against a chess player. And he played draw against 3 draughts players and 2 chess players. Jannes won the rest.

17. Oldest (and rarest!) draughts book

A book of Torquemada (Spain, Malaga, 1547). A book about Spanish draughts.

18. Oldest notation of a international draughts game

G. Grégoire - A. Verhaeren (1877). Two players from Belgium
Wit: G. Grégoire - Zwart: A. Verhaeren

19. Longest game (in moves)

The duration of a game is normally 50-65 moves. In a extreme situation 100 moves of more.

The 3 longest (official) games:
1. D. van Os - M. Meijer: 137 moves (1-1)
2. O. Drenth - H. van der Zee: 136 moves (1-1)
3. Herman Meijer - M. Visser: 128 moves (1-1)
 

The longest game:
White: D. van Os - Black: M. Meijer

The longest game that not resulted in a draw: E. Bronstring - F. Luteyn.
Bronstring defeated Luteyn in 1980 in 122 moves.

20. Biggest difference in strongness between 2 players.

World Championship 1968.

Russian player Iser Koeperman, at that moment the player with the highest ranking in the world, against G. Feldl from Austria, the weakest player ever. Play and astonish!
White: G. Feldl - Black: I. Koeperman