Send her to the games. There will be an option to Create Account a little ways down from the top, towards the left.

http://www.funtrivia.com/private/main.cfm?tid=15040

If she wants to join both, tell her to log out of the first game, then use the same user name to register for the second game. On the page for the other game again go to Create Account, and use the same log in info as the first time.

http://www.funtrivia.com/private/main.cfm?tid=75411