You have to read the instructions carefully. The anonymous password for most CVS servers is empty, you just press ENTER. The OpenACS CVS works this way as well.
Anonymous CVS Access
This project's SourceForge.net CVS repository can be checked out through anonymous (pserver) CVS with the following instruction set. The module you wish to check out must be specified as the modulename. When prompted for a password for anonymous, simply press the Enter key. To determine the names of the modules created by this project, you may examine their CVS repository via the provided web-based CVS repository viewer.