Racketlon is a (individual) quadrathlon consisting of table tennis, badminton, squash, and tennis. In each discipline, you play a game against the same opponent and the player who scores the most points over those four games, wins the match. The sport started in Scandinavia in the 1990s and has been played in the Netherlands for about 10 years.
If you would like to try it some time, you can participate in the Student’s racketlon championships, which are being held on May 1st in Groningen. You can enroll through this link: http://toernooi.nl/sport/tournament.aspx?id=FBB55600-0F69-481A-A3F5-33AE3E574F70. Also beginners, or people who don’t master every sport equally well, are very welcome!