Step 1: Make up a short password, such as xyz123.
Step 2: Create and upload a page called xyz123.html (this is the password-protected page).
Step 3: Add the code in the box below to the <head> section of the page where you want the visitor to enter a password.
Step 5: Tell selected people the password (xyz123 in this example).
Test it! The password is "mars".
This is a rip-off of Gate Keeper v2.0 by Joe Barta, which used to be available from http://junior.apk.net/~jbarta/weblinks/gate_keeper/.