Monica and Chandler purposely lose to his boss and his boss' wife. At the tender age of 13, Matthew Perry was a nationally ranked tennis player in Canada.
The movie that Joey and Phoebe go see, You've Got Mail (1998) was actually in theaters at this time. It released in December 1998 and this episode premiered on January 1999.
The magna-doodle changes to "J- Kim called again"
The Magna-doodle says "Joey call Kim".